31561597 has 2 divisors, whose sum is σ = 31561598. Its totient is φ = 31561596.

The previous prime is 31561577. The next prime is 31561631. The reversal of 31561597 is 79516513.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15832441 + 15729156 = 3979^2 + 3966^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31561597 is a prime.

It is a super-2 number, since 2×31561597² = 1992268810380818, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31561547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15780798 + 15780799.

It is an arithmetic number, because the mean of its divisors is an integer number (15780799).

Almost surely, 2^31561597 is an apocalyptic number.

It is an amenable number.

31561597 is a deficient number, since it is larger than the sum of its proper divisors (1).

31561597 is an equidigital number, since it uses as much as digits as its factorization.

31561597 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28350, while the sum is 37.

The square root of 31561597 is about 5617.9708970410. The cubic root of 31561597 is about 316.0237023561.

It can be divided in two parts, 3156 and 1597, that added together give a triangular number (4753 = T₉₇).

The spelling of 31561597 in words is "thirty-one million, five hundred sixty-one thousand, five hundred ninety-seven".