91477891 has 4 divisors (see below), whose sum is σ = 92766384. Its totient is φ = 90189400.

The previous prime is 91477879. The next prime is 91477909. The reversal of 91477891 is 19877419.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19877419 = 1223 ⋅16253.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91477891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91477811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 644140 + ... + 644281.

It is an arithmetic number, because the mean of its divisors is an integer number (23191596).

Almost surely, 2^91477891 is an apocalyptic number.

91477891 is a deficient number, since it is larger than the sum of its proper divisors (1288493).

91477891 is a wasteful number, since it uses less digits than its factorization.

91477891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1288492.

The product of its digits is 127008, while the sum is 46.

The square root of 91477891 is about 9564.4075090933. The cubic root of 91477891 is about 450.5801422912.

The spelling of 91477891 in words is "ninety-one million, four hundred seventy-seven thousand, eight hundred ninety-one".