31313218997 has 2 divisors, whose sum is σ = 31313218998. Its totient is φ = 31313218996.

The previous prime is 31313218991. The next prime is 31313219033. The reversal of 31313218997 is 79981231313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27077031601 + 4236187396 = 164551^2 + 65086^2 .

It is a cyclic number.

It is not a de Polignac number, because 31313218997 - 2³⁰ = 30239477173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31313218991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15656609498 + 15656609499.

It is an arithmetic number, because the mean of its divisors is an integer number (15656609499).

Almost surely, 2^31313218997 is an apocalyptic number.

It is an amenable number.

31313218997 is a deficient number, since it is larger than the sum of its proper divisors (1).

31313218997 is an equidigital number, since it uses as much as digits as its factorization.

31313218997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 47.

The spelling of 31313218997 in words is "thirty-one billion, three hundred thirteen million, two hundred eighteen thousand, nine hundred ninety-seven".