991337531 has 2 divisors, whose sum is σ = 991337532. Its totient is φ = 991337530.

The previous prime is 991337527. The next prime is 991337563. The reversal of 991337531 is 135733199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991337531 - 2² = 991337527 is a prime.

It is a super-2 number, since 2×991337531² = 1965500200738351922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (991337731) 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, 495668765 + 495668766.

It is an arithmetic number, because the mean of its divisors is an integer number (495668766).

Almost surely, 2^991337531 is an apocalyptic number.

991337531 is a deficient number, since it is larger than the sum of its proper divisors (1).

991337531 is an equidigital number, since it uses as much as digits as its factorization.

991337531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 76545, while the sum is 41.

The square root of 991337531 is about 31485.5130337748. The cubic root of 991337531 is about 997.1041323790.

The spelling of 991337531 in words is "nine hundred ninety-one million, three hundred thirty-seven thousand, five hundred thirty-one".