866808989 has 2 divisors, whose sum is σ = 866808990. Its totient is φ = 866808988.

The previous prime is 866808983. The next prime is 866809037. The reversal of 866808989 is 989808668.

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., 688800025 + 178008964 = 26245^2 + 13342^2 .

It is a cyclic number.

It is not a de Polignac number, because 866808989 - 2⁴ = 866808973 is a prime.

It is a super-2 number, since 2×866808989² = 1502715646822404242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866808983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433404494 + 433404495.

It is an arithmetic number, because the mean of its divisors is an integer number (433404495).

Almost surely, 2^866808989 is an apocalyptic number.

It is an amenable number.

866808989 is a deficient number, since it is larger than the sum of its proper divisors (1).

866808989 is an equidigital number, since it uses as much as digits as its factorization.

866808989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11943936, while the sum is 62.

The square root of 866808989 is about 29441.6200131718. The cubic root of 866808989 is about 953.4716887102.

The spelling of 866808989 in words is "eight hundred sixty-six million, eight hundred eight thousand, nine hundred eighty-nine".