8637313921 has 2 divisors, whose sum is σ = 8637313922. Its totient is φ = 8637313920.

The previous prime is 8637313889. The next prime is 8637313963. The reversal of 8637313921 is 1293137368.

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., 5709313600 + 2928000321 = 75560^2 + 54111^2 .

It is a cyclic number.

It is not a de Polignac number, because 8637313921 - 2⁵ = 8637313889 is a prime.

It is not a weakly prime, because it can be changed into another prime (8637313621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4318656960 + 4318656961.

It is an arithmetic number, because the mean of its divisors is an integer number (4318656961).

Almost surely, 2^8637313921 is an apocalyptic number.

It is an amenable number.

8637313921 is a deficient number, since it is larger than the sum of its proper divisors (1).

8637313921 is an equidigital number, since it uses as much as digits as its factorization.

8637313921 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 square root of 8637313921 is about 92937.1503813195. The cubic root of 8637313921 is about 2051.7584690423.

The spelling of 8637313921 in words is "eight billion, six hundred thirty-seven million, three hundred thirteen thousand, nine hundred twenty-one".