1221511512 has 32 divisors (see below), whose sum is σ = 3288685680. Its totient is φ = 375849600.

The previous prime is 1221511493. The next prime is 1221511541. The reversal of 1221511512 is 2151151221.

It is a super-2 number, since 2×1221511512² = 2984180747897052288, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1957239 + ... + 1957862.

Almost surely, 2^1221511512 is an apocalyptic number.

1221511512 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1221511512 is an abundant number, since it is smaller than the sum of its proper divisors (2067174168).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221511512 is a wasteful number, since it uses less digits than its factorization.

1221511512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3915123 (or 3915119 counting only the distinct ones).

The product of its digits is 200, while the sum is 21.

The square root of 1221511512 is about 34950.1289268008. The cubic root of 1221511512 is about 1068.9708309586.

Adding to 1221511512 its reverse (2151151221), we get a palindrome (3372662733).

The spelling of 1221511512 in words is "one billion, two hundred twenty-one million, five hundred eleven thousand, five hundred twelve".