78402915 has 24 divisors (see below), whose sum is σ = 136317168. Its totient is φ = 41686080.

The previous prime is 78402901. The next prime is 78402941. The reversal of 78402915 is 51920487.

It is not a de Polignac number, because 78402915 - 2⁶ = 78402851 is a prime.

It is a super-2 number, since 2×78402915² = 12294034160994450, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78402915.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13105 + ... + 18125.

It is an arithmetic number, because the mean of its divisors is an integer number (5679882).

Almost surely, 2^78402915 is an apocalyptic number.

78402915 is a deficient number, since it is larger than the sum of its proper divisors (57914253).

78402915 is a wasteful number, since it uses less digits than its factorization.

78402915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5379 (or 5376 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 78402915 is about 8854.5420547875. The cubic root of 78402915 is about 428.0002966050. Note that the first 3 decimals are identical.

The spelling of 78402915 in words is "seventy-eight million, four hundred two thousand, nine hundred fifteen".