21156506312 has 16 divisors (see below), whose sum is σ = 39897749340. Its totient is φ = 10517106496.

The previous prime is 21156506311. The next prime is 21156506339. The reversal of 21156506312 is 21360565112.

It can be written as a sum of positive squares in 2 ways, for example, as 15563560516 + 5592945796 = 124754^2 + 74786^2 .

It is not an unprimeable number, because it can be changed into a prime (21156506311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7641863 + ... + 7644630.

Almost surely, 2^21156506312 is an apocalyptic number.

It is an amenable number.

21156506312 is a deficient number, since it is larger than the sum of its proper divisors (18741243028).

21156506312 is a wasteful number, since it uses less digits than its factorization.

21156506312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15286672 (or 15286668 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

The spelling of 21156506312 in words is "twenty-one billion, one hundred fifty-six million, five hundred six thousand, three hundred twelve".