21555655512 has 32 divisors (see below), whose sum is σ = 57059089200. Its totient is φ = 6762558464.

The previous prime is 21555655501. The next prime is 21555655549.

21555655512 is nontrivially palindromic in base 10.

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, 26415837 + ... + 26416652.

Almost surely, 2^21555655512 is an apocalyptic number.

It is an amenable number.

21555655512 is an abundant number, since it is smaller than the sum of its proper divisors (35503433688).

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

21555655512 is a wasteful number, since it uses less digits than its factorization.

21555655512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52832515 (or 52832511 counting only the distinct ones).

The product of its digits is 375000, while the sum is 42.

The spelling of 21555655512 in words is "twenty-one billion, five hundred fifty-five million, six hundred fifty-five thousand, five hundred twelve".