31693621 has 2 divisors, whose sum is σ = 31693622. Its totient is φ = 31693620.

The previous prime is 31693601. The next prime is 31693631. The reversal of 31693621 is 12639613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30371121 + 1322500 = 5511^2 + 1150^2 .

It is a cyclic number.

It is not a de Polignac number, because 31693621 - 2²³ = 23305013 is a prime.

It is a super-2 number, since 2×31693621² = 2008971224183282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31693601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15846810 + 15846811.

It is an arithmetic number, because the mean of its divisors is an integer number (15846811).

Almost surely, 2^31693621 is an apocalyptic number.

It is an amenable number.

31693621 is a deficient number, since it is larger than the sum of its proper divisors (1).

31693621 is an equidigital number, since it uses as much as digits as its factorization.

31693621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5832, while the sum is 31.

The square root of 31693621 is about 5629.7087846531. The cubic root of 31693621 is about 316.4637378832.

The spelling of 31693621 in words is "thirty-one million, six hundred ninety-three thousand, six hundred twenty-one".