991502131 has 2 divisors, whose sum is σ = 991502132. Its totient is φ = 991502130.

The previous prime is 991502123. The next prime is 991502143. The reversal of 991502131 is 131205199.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991502131 - 2³ = 991502123 is a prime.

It is a super-2 number, since 2×991502131² = 1966152951555082322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 991502093 and 991502102.

It is not a weakly prime, because it can be changed into another prime (991502231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495751065 + 495751066.

It is an arithmetic number, because the mean of its divisors is an integer number (495751066).

Almost surely, 2^991502131 is an apocalyptic number.

991502131 is a deficient number, since it is larger than the sum of its proper divisors (1).

991502131 is an equidigital number, since it uses as much as digits as its factorization.

991502131 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2430, while the sum is 31.

The square root of 991502131 is about 31488.1268258371. The cubic root of 991502131 is about 997.1593151505.

The spelling of 991502131 in words is "nine hundred ninety-one million, five hundred two thousand, one hundred thirty-one".