8566691989 has 2 divisors, whose sum is σ = 8566691990. Its totient is φ = 8566691988.

The previous prime is 8566691983. The next prime is 8566692041. The reversal of 8566691989 is 9891966658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7714635889 + 852056100 = 87833^2 + 29190^2 .

It is a cyclic number.

It is not a de Polignac number, because 8566691989 - 2²⁷ = 8432474261 is a prime.

It is a super-2 number, since 2×8566691989² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8566691983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4283345994 + 4283345995.

It is an arithmetic number, because the mean of its divisors is an integer number (4283345995).

Almost surely, 2^8566691989 is an apocalyptic number.

It is an amenable number.

8566691989 is a deficient number, since it is larger than the sum of its proper divisors (1).

8566691989 is an equidigital number, since it uses as much as digits as its factorization.

8566691989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 50388480, while the sum is 67.

The square root of 8566691989 is about 92556.4259735649. The cubic root of 8566691989 is about 2046.1511753551.

The spelling of 8566691989 in words is "eight billion, five hundred sixty-six million, six hundred ninety-one thousand, nine hundred eighty-nine".