78857915 has 32 divisors (see below), whose sum is σ = 104011776. Its totient is φ = 57214080.

The previous prime is 78857887. The next prime is 78857921. The reversal of 78857915 is 51975887.

It is not a de Polignac number, because 78857915 - 2⁸ = 78857659 is a prime.

It is a Duffinian number.

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, 182750 + ... + 183180.

It is an arithmetic number, because the mean of its divisors is an integer number (3250368).

Almost surely, 2^78857915 is an apocalyptic number.

78857915 is a deficient number, since it is larger than the sum of its proper divisors (25153861).

78857915 is a wasteful number, since it uses less digits than its factorization.

78857915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 539.

The product of its digits is 705600, while the sum is 50.

The square root of 78857915 is about 8880.1979144611. The cubic root of 78857915 is about 428.8266461075.

The spelling of 78857915 in words is "seventy-eight million, eight hundred fifty-seven thousand, nine hundred fifteen".