91899931 has 2 divisors, whose sum is σ = 91899932. Its totient is φ = 91899930.

The previous prime is 91899923. The next prime is 91899937. The reversal of 91899931 is 13999819.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91899931 - 2³ = 91899923 is a prime.

It is a super-2 number, since 2×91899931² = 16891194635609522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (91899937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45949965 + 45949966.

It is an arithmetic number, because the mean of its divisors is an integer number (45949966).

Almost surely, 2^91899931 is an apocalyptic number.

91899931 is a deficient number, since it is larger than the sum of its proper divisors (1).

91899931 is an equidigital number, since it uses as much as digits as its factorization.

91899931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 157464, while the sum is 49.

The square root of 91899931 is about 9586.4451701348. The cubic root of 91899931 is about 451.2720076334.

The spelling of 91899931 in words is "ninety-one million, eight hundred ninety-nine thousand, nine hundred thirty-one".