8517031921 has 2 divisors, whose sum is σ = 8517031922. Its totient is φ = 8517031920.

The previous prime is 8517031889. The next prime is 8517032023. The reversal of 8517031921 is 1291307158.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8251178896 + 265853025 = 90836^2 + 16305^2 .

It is a cyclic number.

It is not a de Polignac number, because 8517031921 - 2⁵ = 8517031889 is a prime.

It is not a weakly prime, because it can be changed into another prime (8517031021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4258515960 + 4258515961.

It is an arithmetic number, because the mean of its divisors is an integer number (4258515961).

Almost surely, 2^8517031921 is an apocalyptic number.

It is an amenable number.

8517031921 is a deficient number, since it is larger than the sum of its proper divisors (1).

8517031921 is an equidigital number, since it uses as much as digits as its factorization.

8517031921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 37.

The square root of 8517031921 is about 92287.7669087296. The cubic root of 8517031921 is about 2042.1897479434.

The spelling of 8517031921 in words is "eight billion, five hundred seventeen million, thirty-one thousand, nine hundred twenty-one".