91974399 has 24 divisors (see below), whose sum is σ = 139458480. Its totient is φ = 53813760.

The previous prime is 91974371. The next prime is 91974409. The reversal of 91974399 is 99347919.

91974399 = 370² + 371² + ... + 688².

It is not a de Polignac number, because 91974399 - 2⁵ = 91974367 is a prime.

It is a super-2 number, since 2×91974399² = 16918580142822402, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91974319) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6159 + ... + 14895.

It is an arithmetic number, because the mean of its divisors is an integer number (5810770).

Almost surely, 2^91974399 is an apocalyptic number.

91974399 is a deficient number, since it is larger than the sum of its proper divisors (47484081).

91974399 is a wasteful number, since it uses less digits than its factorization.

91974399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8791 (or 8780 counting only the distinct ones).

The product of its digits is 551124, while the sum is 51.

The square root of 91974399 is about 9590.3284093925. The cubic root of 91974399 is about 451.3938657262.

The spelling of 91974399 in words is "ninety-one million, nine hundred seventy-four thousand, three hundred ninety-nine".