31917364621 has 2 divisors, whose sum is σ = 31917364622. Its totient is φ = 31917364620.

The previous prime is 31917364573. The next prime is 31917364651. The reversal of 31917364621 is 12646371913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22555834596 + 9361530025 = 150186^2 + 96755^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31917364621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31917364651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15958682310 + 15958682311.

It is an arithmetic number, because the mean of its divisors is an integer number (15958682311).

Almost surely, 2^31917364621 is an apocalyptic number.

It is an amenable number.

31917364621 is a deficient number, since it is larger than the sum of its proper divisors (1).

31917364621 is an equidigital number, since it uses as much as digits as its factorization.

31917364621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 43.

The spelling of 31917364621 in words is "thirty-one billion, nine hundred seventeen million, three hundred sixty-four thousand, six hundred twenty-one".