21057212928 has 160 divisors (see below), whose sum is σ = 59539385664. Its totient is φ = 6590431232.

The previous prime is 21057212903. The next prime is 21057213007. The reversal of 21057212928 is 82921275012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16110451 + ... + 16111757.

Almost surely, 2^21057212928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21057212928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29769692832).

21057212928 is an abundant number, since it is smaller than the sum of its proper divisors (38482172736).

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

21057212928 is a wasteful number, since it uses less digits than its factorization.

21057212928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1962 (or 1946 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 39.

The spelling of 21057212928 in words is "twenty-one billion, fifty-seven million, two hundred twelve thousand, nine hundred twenty-eight".