657387989 has 2 divisors, whose sum is σ = 657387990. Its totient is φ = 657387988.

The previous prime is 657387967. The next prime is 657388019. The reversal of 657387989 is 989783756.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 642216964 + 15171025 = 25342^2 + 3895^2 .

It is a cyclic number.

It is not a de Polignac number, because 657387989 - 2⁸ = 657387733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (657387589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328693994 + 328693995.

It is an arithmetic number, because the mean of its divisors is an integer number (328693995).

Almost surely, 2^657387989 is an apocalyptic number.

It is an amenable number.

657387989 is a deficient number, since it is larger than the sum of its proper divisors (1).

657387989 is an equidigital number, since it uses as much as digits as its factorization.

657387989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22861440, while the sum is 62.

The square root of 657387989 is about 25639.5785651793. The cubic root of 657387989 is about 869.5086797358.

The spelling of 657387989 in words is "six hundred fifty-seven million, three hundred eighty-seven thousand, nine hundred eighty-nine".