21025338624 has 54 divisors (see below), whose sum is σ = 60621241226. Its totient is φ = 7008445440.

The previous prime is 21025338547. The next prime is 21025338679. The reversal of 21025338624 is 42683352012.

21025338624 is a `hidden beast` number, since 2 + 1 + 0 + 25 + 3 + 3 + 8 + 624 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19928404224 + 1096934400 = 141168^2 + 33120^2 .

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4560487 + ... + 4565094.

Almost surely, 2^21025338624 is an apocalyptic number.

21025338624 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21025338624 is an abundant number, since it is smaller than the sum of its proper divisors (39595902602).

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

21025338624 is an equidigital number, since it uses as much as digits as its factorization.

21025338624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9125603 (or 9125586 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The spelling of 21025338624 in words is "twenty-one billion, twenty-five million, three hundred thirty-eight thousand, six hundred twenty-four".