31736864689921 has 2 divisors, whose sum is σ = 31736864689922. Its totient is φ = 31736864689920.

The previous prime is 31736864689913. The next prime is 31736864689931. The reversal of 31736864689921 is 12998646863713.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26835135109696 + 4901729580225 = 5180264^2 + 2213985^2 .

It is a cyclic number.

It is not a de Polignac number, because 31736864689921 - 2³ = 31736864689913 is a prime.

It is not a weakly prime, because it can be changed into another prime (31736864689931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15868432344960 + 15868432344961.

It is an arithmetic number, because the mean of its divisors is an integer number (15868432344961).

Almost surely, 2^{31736864689921} is an apocalyptic number.

It is an amenable number.

31736864689921 is a deficient number, since it is larger than the sum of its proper divisors (1).

31736864689921 is an equidigital number, since it uses as much as digits as its factorization.

31736864689921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 564350976, while the sum is 73.

The spelling of 31736864689921 in words is "thirty-one trillion, seven hundred thirty-six billion, eight hundred sixty-four million, six hundred eighty-nine thousand, nine hundred twenty-one".