31324716581 has 2 divisors, whose sum is σ = 31324716582. Its totient is φ = 31324716580.

The previous prime is 31324716539. The next prime is 31324716593. The reversal of 31324716581 is 18561742313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29837380225 + 1487336356 = 172735^2 + 38566^2 .

It is a cyclic number.

It is not a de Polignac number, because 31324716581 - 2³⁴ = 14144847397 is a prime.

It is a super-2 number, since 2×31324716581² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31324736581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15662358290 + 15662358291.

It is an arithmetic number, because the mean of its divisors is an integer number (15662358291).

Almost surely, 2^31324716581 is an apocalyptic number.

It is an amenable number.

31324716581 is a deficient number, since it is larger than the sum of its proper divisors (1).

31324716581 is an equidigital number, since it uses as much as digits as its factorization.

31324716581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 41.

The spelling of 31324716581 in words is "thirty-one billion, three hundred twenty-four million, seven hundred sixteen thousand, five hundred eighty-one".