78864915 has 32 divisors (see below), whose sum is σ = 133701120. Its totient is φ = 39585024.

The previous prime is 78864913. The next prime is 78864917. The reversal of 78864915 is 51946887.

It is an interprime number because it is at equal distance from previous prime (78864913) and next prime (78864917).

It is not a de Polignac number, because 78864915 - 2¹ = 78864913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78864913) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 46767 + ... + 48423.

It is an arithmetic number, because the mean of its divisors is an integer number (4178160).

Almost surely, 2^78864915 is an apocalyptic number.

78864915 is a deficient number, since it is larger than the sum of its proper divisors (54836205).

78864915 is a wasteful number, since it uses less digits than its factorization.

78864915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1851.

The product of its digits is 483840, while the sum is 48.

The square root of 78864915 is about 8880.5920410747. The cubic root of 78864915 is about 428.8393343190.

It can be divided in two parts, 788 and 64915, that added together give a triangular number (65703 = T₃₆₂).

The spelling of 78864915 in words is "seventy-eight million, eight hundred sixty-four thousand, nine hundred fifteen".