6817564889 has 2 divisors, whose sum is σ = 6817564890. Its totient is φ = 6817564888.

The previous prime is 6817564883. The next prime is 6817564909. The reversal of 6817564889 is 9884657186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3756709264 + 3060855625 = 61292^2 + 55325^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6817564889 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (6817564883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3408782444 + 3408782445.

It is an arithmetic number, because the mean of its divisors is an integer number (3408782445).

Almost surely, 2^6817564889 is an apocalyptic number.

It is an amenable number.

6817564889 is a deficient number, since it is larger than the sum of its proper divisors (1).

6817564889 is an equidigital number, since it uses as much as digits as its factorization.

6817564889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23224320, while the sum is 62.

The square root of 6817564889 is about 82568.5466082576. The cubic root of 6817564889 is about 1896.1663131636.

The spelling of 6817564889 in words is "six billion, eight hundred seventeen million, five hundred sixty-four thousand, eight hundred eighty-nine".