21250933728 has 48 divisors (see below), whose sum is σ = 55802834640. Its totient is φ = 7081214976.

The previous prime is 21250933681. The next prime is 21250933733. The reversal of 21250933728 is 82733905212.

It is a Cunningham number, because it is equal to 145777²-1.

It is a tau number, because it is divible by the number of its divisors (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21250933728.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 255108 + ... + 327996.

It is an arithmetic number, because the mean of its divisors is an integer number (1162559055).

Almost surely, 2^21250933728 is an apocalyptic number.

It is an amenable number.

21250933728 is an abundant number, since it is smaller than the sum of its proper divisors (34551900912).

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

21250933728 is a wasteful number, since it uses less digits than its factorization.

21250933728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75939 (or 75931 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 42.

The spelling of 21250933728 in words is "twenty-one billion, two hundred fifty million, nine hundred thirty-three thousand, seven hundred twenty-eight".