31331161 has 2 divisors, whose sum is σ = 31331162. Its totient is φ = 31331160.

The previous prime is 31331149. The next prime is 31331177. The reversal of 31331161 is 16113313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27625536 + 3705625 = 5256^2 + 1925^2 .

It is a cyclic number.

It is not a de Polignac number, because 31331161 - 2⁷ = 31331033 is a prime.

It is not a weakly prime, because it can be changed into another prime (31331101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15665580 + 15665581.

It is an arithmetic number, because the mean of its divisors is an integer number (15665581).

Almost surely, 2^31331161 is an apocalyptic number.

It is an amenable number.

31331161 is a deficient number, since it is larger than the sum of its proper divisors (1).

31331161 is an equidigital number, since it uses as much as digits as its factorization.

31331161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 162, while the sum is 19.

The square root of 31331161 is about 5597.4244970343. The cubic root of 31331161 is about 315.2527106195.

Adding to 31331161 its reverse (16113313), we get a palindrome (47444474).

The spelling of 31331161 in words is "thirty-one million, three hundred thirty-one thousand, one hundred sixty-one".