78826815 has 12 divisors (see below), whose sum is σ = 136633224. Its totient is φ = 42040944.

The previous prime is 78826789. The next prime is 78826817. The reversal of 78826815 is 51862887.

It is not a de Polignac number, because 78826815 - 2⁹ = 78826303 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 1751707 = 78826815 / (7 + 8 + 8 + 2 + 6 + 8 + 1 + 5).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78826817) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 875809 + ... + 875898.

It is an arithmetic number, because the mean of its divisors is an integer number (11386102).

Almost surely, 2^78826815 is an apocalyptic number.

78826815 is a deficient number, since it is larger than the sum of its proper divisors (57806409).

78826815 is a wasteful number, since it uses less digits than its factorization.

78826815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1751718 (or 1751715 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 78826815 is about 8878.4466546801. The cubic root of 78826815 is about 428.7702651161.

The spelling of 78826815 in words is "seventy-eight million, eight hundred twenty-six thousand, eight hundred fifteen".