81917315 has 32 divisors (see below), whose sum is σ = 105494400. Its totient is φ = 60963840.

The previous prime is 81917309. The next prime is 81917323. The reversal of 81917315 is 51371918.

It is not a de Polignac number, because 81917315 - 2²⁴ = 65140099 is a prime.

It is a super-3 number, since 3×81917315³ (a number of 25 digits) contains 333 as substring.

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, 751481 + ... + 751589.

It is an arithmetic number, because the mean of its divisors is an integer number (3296700).

Almost surely, 2^81917315 is an apocalyptic number.

81917315 is a deficient number, since it is larger than the sum of its proper divisors (23577085).

81917315 is a wasteful number, since it uses less digits than its factorization.

81917315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287.

The product of its digits is 7560, while the sum is 35.

The square root of 81917315 is about 9050.8184712765. The cubic root of 81917315 is about 434.3020736741.

The spelling of 81917315 in words is "eighty-one million, nine hundred seventeen thousand, three hundred fifteen".