21305513328 has 40 divisors (see below), whose sum is σ = 60042811776. Its totient is φ = 6456216000.

The previous prime is 21305513311. The next prime is 21305513353. The reversal of 21305513328 is 82331550312.

It is a Harshad number since it is a multiple of its sum of digits (33).

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, 20175148 + ... + 20176203.

Almost surely, 2^21305513328 is an apocalyptic number.

It is an amenable number.

21305513328 is an abundant number, since it is smaller than the sum of its proper divisors (38737298448).

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

21305513328 is a wasteful number, since it uses less digits than its factorization.

21305513328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40351373 (or 40351367 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 33.

The spelling of 21305513328 in words is "twenty-one billion, three hundred five million, five hundred thirteen thousand, three hundred twenty-eight".