31385491 has 2 divisors, whose sum is σ = 31385492. Its totient is φ = 31385490.

The previous prime is 31385489. The next prime is 31385503. The reversal of 31385491 is 19458313.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31385491 - 2¹ = 31385489 is a prime.

It is a super-2 number, since 2×31385491² = 1970098090622162, which contains 22 as substring.

Together with 31385489, it forms a pair of twin primes.

It is equal to p_1938247 and since 31385491 and 1938247 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (31385461) 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, 15692745 + 15692746.

It is an arithmetic number, because the mean of its divisors is an integer number (15692746).

Almost surely, 2^31385491 is an apocalyptic number.

31385491 is a deficient number, since it is larger than the sum of its proper divisors (1).

31385491 is an equidigital number, since it uses as much as digits as its factorization.

31385491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 34.

The square root of 31385491 is about 5602.2755198223. The cubic root of 31385491 is about 315.4348273857.

The spelling of 31385491 in words is "thirty-one million, three hundred eighty-five thousand, four hundred ninety-one".