7818989 has 2 divisors, whose sum is σ = 7818990. Its totient is φ = 7818988.

The previous prime is 7818977. The next prime is 7819033. The reversal of 7818989 is 9898187.

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., 6461764 + 1357225 = 2542^2 + 1165^2 .

It is a cyclic number.

It is not a de Polignac number, because 7818989 - 2⁴ = 7818973 is a prime.

It is a super-2 number, since 2×7818989² = 122273177964242, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7818949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3909494 + 3909495.

It is an arithmetic number, because the mean of its divisors is an integer number (3909495).

Almost surely, 2^7818989 is an apocalyptic number.

It is an amenable number.

7818989 is a deficient number, since it is larger than the sum of its proper divisors (1).

7818989 is an equidigital number, since it uses as much as digits as its factorization.

7818989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 50.

The square root of 7818989 is about 2796.2455185480. The cubic root of 7818989 is about 198.4800530686.

The spelling of 7818989 in words is "seven million, eight hundred eighteen thousand, nine hundred eighty-nine".