31939213 has 2 divisors, whose sum is σ = 31939214. Its totient is φ = 31939212.

The previous prime is 31939199. The next prime is 31939217. The reversal of 31939213 is 31293913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30713764 + 1225449 = 5542^2 + 1107^2 .

It is a cyclic number.

It is not a de Polignac number, because 31939213 - 2⁵ = 31939181 is a prime.

It is a super-2 number, since 2×31939213² = 2040226654118738, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31939217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15969606 + 15969607.

It is an arithmetic number, because the mean of its divisors is an integer number (15969607).

Almost surely, 2^31939213 is an apocalyptic number.

It is an amenable number.

31939213 is a deficient number, since it is larger than the sum of its proper divisors (1).

31939213 is an equidigital number, since it uses as much as digits as its factorization.

31939213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4374, while the sum is 31.

The square root of 31939213 is about 5651.4788330135. The cubic root of 31939213 is about 317.2790551609.

The spelling of 31939213 in words is "thirty-one million, nine hundred thirty-nine thousand, two hundred thirteen".