78116915 has 4 divisors (see below), whose sum is σ = 93740304. Its totient is φ = 62493528.

The previous prime is 78116893. The next prime is 78116933. The reversal of 78116915 is 51961187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51961187 = 6353 ⋅8179.

It is a cyclic number.

It is not a de Polignac number, because 78116915 - 2⁸ = 78116659 is a prime.

It is a super-2 number, since 2×78116915² = 12204504818234450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7811687 + ... + 7811696.

It is an arithmetic number, because the mean of its divisors is an integer number (23435076).

Almost surely, 2^78116915 is an apocalyptic number.

78116915 is a deficient number, since it is larger than the sum of its proper divisors (15623389).

78116915 is a wasteful number, since it uses less digits than its factorization.

78116915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15623388.

The product of its digits is 15120, while the sum is 38.

The square root of 78116915 is about 8838.3773963324. The cubic root of 78116915 is about 427.4792393279.

The spelling of 78116915 in words is "seventy-eight million, one hundred sixteen thousand, nine hundred fifteen".