7899989 has 2 divisors, whose sum is σ = 7899990. Its totient is φ = 7899988.

The previous prime is 7899979. The next prime is 7900001. The reversal of 7899989 is 9899987.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4695889 + 3204100 = 2167^2 + 1790^2 .

It is a cyclic number.

It is not a de Polignac number, because 7899989 - 2⁸ = 7899733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7899929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3949994 + 3949995.

It is an arithmetic number, because the mean of its divisors is an integer number (3949995).

Almost surely, 2^7899989 is an apocalyptic number.

It is an amenable number.

7899989 is a deficient number, since it is larger than the sum of its proper divisors (1).

7899989 is an equidigital number, since it uses as much as digits as its factorization.

7899989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2939328, while the sum is 59.

The square root of 7899989 is about 2810.6919076982. The cubic root of 7899989 is about 199.1630776903.

It can be divided in two parts, 7899 and 989, that added together give a palindrome (8888).

The spelling of 7899989 in words is "seven million, eight hundred ninety-nine thousand, nine hundred eighty-nine".