31918643 has 2 divisors, whose sum is σ = 31918644. Its totient is φ = 31918642.

The previous prime is 31918619. The next prime is 31918657. The reversal of 31918643 is 34681913.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31918643 - 2⁸ = 31918387 is a prime.

It is a super-2 number, since 2×31918643² = 2037599541922898, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31998643) 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, 15959321 + 15959322.

It is an arithmetic number, because the mean of its divisors is an integer number (15959322).

Almost surely, 2^31918643 is an apocalyptic number.

31918643 is a deficient number, since it is larger than the sum of its proper divisors (1).

31918643 is an equidigital number, since it uses as much as digits as its factorization.

31918643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 35.

The square root of 31918643 is about 5649.6586622556. The cubic root of 31918643 is about 317.2109274987.

The spelling of 31918643 in words is "thirty-one million, nine hundred eighteen thousand, six hundred forty-three".