31625681 has 2 divisors, whose sum is σ = 31625682. Its totient is φ = 31625680.

The previous prime is 31625653. The next prime is 31625723. The reversal of 31625681 is 18652613.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26173456 + 5452225 = 5116^2 + 2335^2 .

It is a cyclic number.

It is not a de Polignac number, because 31625681 - 2⁶ = 31625617 is a prime.

It is a super-2 number, since 2×31625681² = 2000367397427522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31625651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15812840 + 15812841.

It is an arithmetic number, because the mean of its divisors is an integer number (15812841).

Almost surely, 2^31625681 is an apocalyptic number.

It is an amenable number.

31625681 is a deficient number, since it is larger than the sum of its proper divisors (1).

31625681 is an equidigital number, since it uses as much as digits as its factorization.

31625681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 32.

The square root of 31625681 is about 5623.6714875604. The cubic root of 31625681 is about 316.2374470482.

The spelling of 31625681 in words is "thirty-one million, six hundred twenty-five thousand, six hundred eighty-one".