When applying for benefits, the Social Security Administration will assign a "Beneficiary Identification Code" (BIC) after your Social Security number.
So in paperwork from the SSA, you may see the following codes appended after your Social Security number :
& Combined A and B beneficiary in the same payment
A Primary claimant
B Aged wife, age 62 or over (1st claimant)
B1 Aged husband, age 62 or over (1st claimant)
B2 Young wife, with a child in her care (1st claimant)
B3 Aged wife (2nd claimant)
B4 Aged husband (2nd claimant)
B5 Young wife (2nd claimant)
B6 Divorced wife, age 62 or over (1st claimant)
B7 Young wife (3rd claimant)
B8 Aged wife (3rd claimant)
B9 Divorced wife (2nd claimant)
BA Aged wife (4th claimant)
BD Aged wife (5th claimant)
BG Aged husband (3rd claimant)
BH Aged husband (4th claimant)
BJ Aged husband (5th claimant)
BK Young wife (4th claimant)
BL Young wife (5th claimant)
BN Divorced wife (3rd claimant)
BP Divorced wife (4th claimant)
BQ Divorced wife (5th claimant)
BR Divorced husband, age 62 or older 1st claimant)
BT Divorced husband (2nd claimant)
BW Young husband (2nd claimant)
BY Young husband, with a child in his care (1st claimant)
C1-C9 Child (includes minor, student or disabled child)
CA-CK Child (includes minor, student or disabled child)
D Aged widow, age 60 or over (1st claimant)
D1 Aged widower, age 60 or over (1st claimant)
D2 Aged widow (2nd claimant)
D3 Aged widower (2nd claimant)
D4 Widow (remarried after attainment of age 60) (1st claimant)
D5 Widower (remarried after attainment of age 60) (1st claimant)
D6 Surviving divorced wife, age 60 or over (1st claimant)
D7 Surviving divorced wife (2nd claimant)
D8 Aged widow (3rd claimant)
D9 Remarried widow (2nd claimant)
DA Remarried widow (3rd claimant)
DC Surviving divorced husband, age 60 or over (1st claimant)
DD Aged widow (4th claimant)