31316881 has 2 divisors, whose sum is σ = 31316882. Its totient is φ = 31316880.

The previous prime is 31316861. The next prime is 31316917. The reversal of 31316881 is 18861313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31259281 + 57600 = 5591^2 + 240^2 .

It is a cyclic number.

It is not a de Polignac number, because 31316881 - 2⁵ = 31316849 is a prime.

It is a super-2 number, since 2×31316881² = 1961494071136322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31316821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15658440 + 15658441.

It is an arithmetic number, because the mean of its divisors is an integer number (15658441).

Almost surely, 2^31316881 is an apocalyptic number.

It is an amenable number.

31316881 is a deficient number, since it is larger than the sum of its proper divisors (1).

31316881 is an equidigital number, since it uses as much as digits as its factorization.

31316881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 31.

The square root of 31316881 is about 5596.1487649990. The cubic root of 31316881 is about 315.2048084386.

The spelling of 31316881 in words is "thirty-one million, three hundred sixteen thousand, eight hundred eighty-one".