31906531 has 2 divisors, whose sum is σ = 31906532. Its totient is φ = 31906530.

The previous prime is 31906517. The next prime is 31906541. The reversal of 31906531 is 13560913.

It is a strong prime.

It is an emirp because it is prime and its reverse (13560913) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31906531 - 2⁹ = 31906019 is a prime.

It is a super-2 number, since 2×31906531² = 2036053440907922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31906531.

It is not a weakly prime, because it can be changed into another prime (31906541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15953265 + 15953266.

It is an arithmetic number, because the mean of its divisors is an integer number (15953266).

Almost surely, 2^31906531 is an apocalyptic number.

31906531 is a deficient number, since it is larger than the sum of its proper divisors (1).

31906531 is an equidigital number, since it uses as much as digits as its factorization.

31906531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2430, while the sum is 28.

The square root of 31906531 is about 5648.5866373811. The cubic root of 31906531 is about 317.1707989670.

The spelling of 31906531 in words is "thirty-one million, nine hundred six thousand, five hundred thirty-one".