91979191 has 4 divisors (see below), whose sum is σ = 92037352. Its totient is φ = 91921032.

The previous prime is 91979149. The next prime is 91979207. The reversal of 91979191 is 19197919.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91979191 - 2¹³ = 91970999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91979101) 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, 26640 + ... + 29893.

It is an arithmetic number, because the mean of its divisors is an integer number (23009338).

Almost surely, 2^91979191 is an apocalyptic number.

91979191 is a deficient number, since it is larger than the sum of its proper divisors (58161).

91979191 is a wasteful number, since it uses less digits than its factorization.

91979191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58160.

The product of its digits is 45927, while the sum is 46.

The square root of 91979191 is about 9590.5782411698. The cubic root of 91979191 is about 451.4017050158.

The spelling of 91979191 in words is "ninety-one million, nine hundred seventy-nine thousand, one hundred ninety-one".