656189509 has 2 divisors, whose sum is σ = 656189510. Its totient is φ = 656189508.

The previous prime is 656189489. The next prime is 656189537. The reversal of 656189509 is 905981656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 540562500 + 115627009 = 23250^2 + 10753^2 .

It is a cyclic number.

It is not a de Polignac number, because 656189509 - 2⁷ = 656189381 is a prime.

It is a super-2 number, since 2×656189509² = 861169343443322162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656189539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328094754 + 328094755.

It is an arithmetic number, because the mean of its divisors is an integer number (328094755).

Almost surely, 2^656189509 is an apocalyptic number.

It is an amenable number.

656189509 is a deficient number, since it is larger than the sum of its proper divisors (1).

656189509 is an equidigital number, since it uses as much as digits as its factorization.

656189509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 583200, while the sum is 49.

The square root of 656189509 is about 25616.1962242641. The cubic root of 656189509 is about 868.9799596611.

The spelling of 656189509 in words is "six hundred fifty-six million, one hundred eighty-nine thousand, five hundred nine".