31667464721 has 2 divisors, whose sum is σ = 31667464722. Its totient is φ = 31667464720.

The previous prime is 31667464613. The next prime is 31667464723. The reversal of 31667464721 is 12746476613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19110021121 + 12557443600 = 138239^2 + 112060^2 .

It is a cyclic number.

It is not a de Polignac number, because 31667464721 - 2¹⁸ = 31667202577 is a prime.

Together with 31667464723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31667464723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15833732360 + 15833732361.

It is an arithmetic number, because the mean of its divisors is an integer number (15833732361).

Almost surely, 2^31667464721 is an apocalyptic number.

It is an amenable number.

31667464721 is a deficient number, since it is larger than the sum of its proper divisors (1).

31667464721 is an equidigital number, since it uses as much as digits as its factorization.

31667464721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1016064, while the sum is 47.

The spelling of 31667464721 in words is "thirty-one billion, six hundred sixty-seven million, four hundred sixty-four thousand, seven hundred twenty-one".