21715261225 has 72 divisors (see below), whose sum is σ = 32070695360. Its totient is φ = 14280416640.

The previous prime is 21715261153. The next prime is 21715261241. The reversal of 21715261225 is 52216251712.

It is not a de Polignac number, because 21715261225 - 2⁷ = 21715261097 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 26194111 + ... + 26194939.

Almost surely, 2^21715261225 is an apocalyptic number.

21715261225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21715261225 is a deficient number, since it is larger than the sum of its proper divisors (10355434135).

21715261225 is an equidigital number, since it uses as much as digits as its factorization.

21715261225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1007 (or 943 counting only the distinct ones).

The product of its digits is 16800, while the sum is 34.

The spelling of 21715261225 in words is "twenty-one billion, seven hundred fifteen million, two hundred sixty-one thousand, two hundred twenty-five".