21139424256 has 88 divisors (see below), whose sum is σ = 58287424320. Its totient is φ = 6803464192.

The previous prime is 21139424239. The next prime is 21139424309. The reversal of 21139424256 is 65242493112.

It is a super-2 number, since 2×21139424256² (a number of 21 digits) contains 22 as substring.

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, 29556 + ... + 207731.

Almost surely, 2^21139424256 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 21139424256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29143712160).

21139424256 is an abundant number, since it is smaller than the sum of its proper divisors (37148000064).

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

21139424256 is a wasteful number, since it uses less digits than its factorization.

21139424256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237339 (or 237321 counting only the distinct ones).

The product of its digits is 103680, while the sum is 39.

The spelling of 21139424256 in words is "twenty-one billion, one hundred thirty-nine million, four hundred twenty-four thousand, two hundred fifty-six".