91878657 has 16 divisors (see below), whose sum is σ = 132507648. Its totient is φ = 56292480.

The previous prime is 91878613. The next prime is 91878667. The reversal of 91878657 is 75687819.

It is not a de Polignac number, because 91878657 - 2¹⁰ = 91877633 is a prime.

It is a super-2 number, since 2×91878657² = 16883375224247298, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91878667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4032 + ... + 14142.

It is an arithmetic number, because the mean of its divisors is an integer number (8281728).

Almost surely, 2^91878657 is an apocalyptic number.

It is an amenable number.

91878657 is a deficient number, since it is larger than the sum of its proper divisors (40628991).

91878657 is a wasteful number, since it uses less digits than its factorization.

91878657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10360.

The product of its digits is 846720, while the sum is 51.

The square root of 91878657 is about 9585.3355183843. The cubic root of 91878657 is about 451.2371831546.

The spelling of 91878657 in words is "ninety-one million, eight hundred seventy-eight thousand, six hundred fifty-seven".