991574131 has 2 divisors, whose sum is σ = 991574132. Its totient is φ = 991574130.

The previous prime is 991574123. The next prime is 991574149. The reversal of 991574131 is 131475199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991574131 - 2³ = 991574123 is a prime.

It is a super-2 number, since 2×991574131² = 1966438514536810322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (991574231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495787065 + 495787066.

It is an arithmetic number, because the mean of its divisors is an integer number (495787066).

Almost surely, 2^991574131 is an apocalyptic number.

991574131 is a deficient number, since it is larger than the sum of its proper divisors (1).

991574131 is an equidigital number, since it uses as much as digits as its factorization.

991574131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34020, while the sum is 40.

The square root of 991574131 is about 31489.2700931603. The cubic root of 991574131 is about 997.1834515024.

The spelling of 991574131 in words is "nine hundred ninety-one million, five hundred seventy-four thousand, one hundred thirty-one".