656989 has 2 divisors, whose sum is σ = 656990. Its totient is φ = 656988.

The previous prime is 656977. The next prime is 656993. The reversal of 656989 is 989656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 632025 + 24964 = 795^2 + 158^2 .

It is a cyclic number.

It is not a de Polignac number, because 656989 - 2¹⁹ = 132701 is a prime.

It is a super-2 number, since 2×656989² = 863269092242, which contains 22 as substring.

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

656989 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328494 + 328495.

It is an arithmetic number, because the mean of its divisors is an integer number (328495).

2⁶⁵⁶⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

656989 is a deficient number, since it is larger than the sum of its proper divisors (1).

656989 is an equidigital number, since it uses as much as digits as its factorization.

656989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 43.

The square root of 656989 is about 810.5485796669. The cubic root of 656989 is about 86.9332733610.

The spelling of 656989 in words is "six hundred fifty-six thousand, nine hundred eighty-nine".