31638869657 has 2 divisors, whose sum is σ = 31638869658. Its totient is φ = 31638869656.

The previous prime is 31638869641. The next prime is 31638869671. The reversal of 31638869657 is 75696883613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31266726976 + 372142681 = 176824^2 + 19291^2 .

It is a cyclic number.

It is not a de Polignac number, because 31638869657 - 2⁴ = 31638869641 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31638869657.

It is not a weakly prime, because it can be changed into another prime (31638869617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15819434828 + 15819434829.

It is an arithmetic number, because the mean of its divisors is an integer number (15819434829).

Almost surely, 2^31638869657 is an apocalyptic number.

It is an amenable number.

31638869657 is a deficient number, since it is larger than the sum of its proper divisors (1).

31638869657 is an equidigital number, since it uses as much as digits as its factorization.

31638869657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39191040, while the sum is 62.

The spelling of 31638869657 in words is "thirty-one billion, six hundred thirty-eight million, eight hundred sixty-nine thousand, six hundred fifty-seven".