656520989 has 2 divisors, whose sum is σ = 656520990. Its totient is φ = 656520988.

The previous prime is 656520973. The next prime is 656521009. The reversal of 656520989 is 989025656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 374112964 + 282408025 = 19342^2 + 16805^2 .

It is a cyclic number.

It is not a de Polignac number, because 656520989 - 2⁴ = 656520973 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656520919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328260494 + 328260495.

It is an arithmetic number, because the mean of its divisors is an integer number (328260495).

Almost surely, 2^656520989 is an apocalyptic number.

It is an amenable number.

656520989 is a deficient number, since it is larger than the sum of its proper divisors (1).

656520989 is an equidigital number, since it uses as much as digits as its factorization.

656520989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1166400, while the sum is 50.

The square root of 656520989 is about 25622.6655326880. The cubic root of 656520989 is about 869.1262593622.

The spelling of 656520989 in words is "six hundred fifty-six million, five hundred twenty thousand, nine hundred eighty-nine".