78766191 has 48 divisors (see below), whose sum is σ = 142871040. Its totient is φ = 40772160.

The previous prime is 78766187. The next prime is 78766199. The reversal of 78766191 is 19166787.

It is not a de Polignac number, because 78766191 - 2² = 78766187 is a prime.

It is a super-2 number, since 2×78766191² = 12408225689296962, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78766199) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 26101 + ... + 28961.

It is an arithmetic number, because the mean of its divisors is an integer number (2976480).

Almost surely, 2^78766191 is an apocalyptic number.

78766191 is a deficient number, since it is larger than the sum of its proper divisors (64104849).

78766191 is a wasteful number, since it uses less digits than its factorization.

78766191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2916 (or 2913 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 78766191 is about 8875.0318872667. The cubic root of 78766191 is about 428.6603176101.

The spelling of 78766191 in words is "seventy-eight million, seven hundred sixty-six thousand, one hundred ninety-one".