31231961 has 2 divisors, whose sum is σ = 31231962. Its totient is φ = 31231960.

The previous prime is 31231951. The next prime is 31232011. The reversal of 31231961 is 16913213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30591961 + 640000 = 5531^2 + 800^2 .

It is an emirp because it is prime and its reverse (16913213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31231961 - 2⁶ = 31231897 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31231961.

It is not a weakly prime, because it can be changed into another prime (31231951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15615980 + 15615981.

It is an arithmetic number, because the mean of its divisors is an integer number (15615981).

Almost surely, 2^31231961 is an apocalyptic number.

It is an amenable number.

31231961 is a deficient number, since it is larger than the sum of its proper divisors (1).

31231961 is an equidigital number, since it uses as much as digits as its factorization.

31231961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 972, while the sum is 26.

The square root of 31231961 is about 5588.5562536312. The cubic root of 31231961 is about 314.9196435660.

The spelling of 31231961 in words is "thirty-one million, two hundred thirty-one thousand, nine hundred sixty-one".