21715015315 has 32 divisors (see below), whose sum is σ = 30756593664. Its totient is φ = 14402776320.

The previous prime is 21715015271. The next prime is 21715015321. The reversal of 21715015315 is 51351051712.

It is not a de Polignac number, because 21715015315 - 2¹⁵ = 21714982547 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3009442 + ... + 3016648.

It is an arithmetic number, because the mean of its divisors is an integer number (961143552).

Almost surely, 2^21715015315 is an apocalyptic number.

21715015315 is a deficient number, since it is larger than the sum of its proper divisors (9041578349).

21715015315 is a wasteful number, since it uses less digits than its factorization.

21715015315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10027.

The product of its (nonzero) digits is 5250, while the sum is 31.

The spelling of 21715015315 in words is "twenty-one billion, seven hundred fifteen million, fifteen thousand, three hundred fifteen".