21390928825 has 12 divisors (see below), whose sum is σ = 30314002240. Its totient is φ = 14668065360.

The previous prime is 21390928799. The next prime is 21390928837. The reversal of 21390928825 is 52882909312.

It is not a de Polignac number, because 21390928825 - 2¹⁹ = 21390404537 is a prime.

It is a hoax number, since the sum of its digits (49) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 61116765 + ... + 61117114.

Almost surely, 2^21390928825 is an apocalyptic number.

21390928825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21390928825 is a deficient number, since it is larger than the sum of its proper divisors (8923073415).

21390928825 is a wasteful number, since it uses less digits than its factorization.

21390928825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122233896 (or 122233891 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 49.

The spelling of 21390928825 in words is "twenty-one billion, three hundred ninety million, nine hundred twenty-eight thousand, eight hundred twenty-five".