31939431 has 4 divisors (see below), whose sum is σ = 42585912. Its totient is φ = 21292952.

The previous prime is 31939429. The next prime is 31939477. The reversal of 31939431 is 13493913.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31939431 - 2¹ = 31939429 is a prime.

It is a super-2 number, since 2×31939431² = 2040254505207522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31939392 and 31939401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31939031) 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 in 3 ways as a sum of consecutive naturals, for example, 5323236 + ... + 5323241.

It is an arithmetic number, because the mean of its divisors is an integer number (10646478).

Almost surely, 2^31939431 is an apocalyptic number.

31939431 is a deficient number, since it is larger than the sum of its proper divisors (10646481).

31939431 is a wasteful number, since it uses less digits than its factorization.

31939431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10646480.

The product of its digits is 8748, while the sum is 33.

The square root of 31939431 is about 5651.4981199678. The cubic root of 31939431 is about 317.2797770184.

The spelling of 31939431 in words is "thirty-one million, nine hundred thirty-nine thousand, four hundred thirty-one".