31121231969 has 2 divisors, whose sum is σ = 31121231970. Its totient is φ = 31121231968.

The previous prime is 31121231959. The next prime is 31121231987. The reversal of 31121231969 is 96913212113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27790557025 + 3330674944 = 166705^2 + 57712^2 .

It is an emirp because it is prime and its reverse (96913212113) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31121231969 is a prime.

It is a super-2 number, since 2×31121231969² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31121231959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15560615984 + 15560615985.

It is an arithmetic number, because the mean of its divisors is an integer number (15560615985).

Almost surely, 2^31121231969 is an apocalyptic number.

It is an amenable number.

31121231969 is a deficient number, since it is larger than the sum of its proper divisors (1).

31121231969 is an equidigital number, since it uses as much as digits as its factorization.

31121231969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17496, while the sum is 38.

The spelling of 31121231969 in words is "thirty-one billion, one hundred twenty-one million, two hundred thirty-one thousand, nine hundred sixty-nine".