21917515315 has 8 divisors (see below), whose sum is σ = 26411065920. Its totient is φ = 17460647232.

The previous prime is 21917515289. The next prime is 21917515363. The reversal of 21917515315 is 51351571912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21917515315 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9169314 + ... + 9171703.

It is an arithmetic number, because the mean of its divisors is an integer number (3301383240).

Almost surely, 2^21917515315 is an apocalyptic number.

21917515315 is a deficient number, since it is larger than the sum of its proper divisors (4493550605).

21917515315 is a wasteful number, since it uses less digits than its factorization.

21917515315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18341261.

The product of its digits is 47250, while the sum is 40.

The spelling of 21917515315 in words is "twenty-one billion, nine hundred seventeen million, five hundred fifteen thousand, three hundred fifteen".