31665961 has 2 divisors, whose sum is σ = 31665962. Its totient is φ = 31665960.

The previous prime is 31665943. The next prime is 31666003. The reversal of 31665961 is 16956613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31147561 + 518400 = 5581^2 + 720^2 .

It is a cyclic number.

It is not a de Polignac number, because 31665961 - 2¹¹ = 31663913 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31665961.

It is not a weakly prime, because it can be changed into another prime (31665061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15832980 + 15832981.

It is an arithmetic number, because the mean of its divisors is an integer number (15832981).

Almost surely, 2^31665961 is an apocalyptic number.

It is an amenable number.

31665961 is a deficient number, since it is larger than the sum of its proper divisors (1).

31665961 is an equidigital number, since it uses as much as digits as its factorization.

31665961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29160, while the sum is 37.

The square root of 31665961 is about 5627.2516382334. The cubic root of 31665961 is about 316.3716485353.

The spelling of 31665961 in words is "thirty-one million, six hundred sixty-five thousand, nine hundred sixty-one".