656991589 has 2 divisors, whose sum is σ = 656991590. Its totient is φ = 656991588.

The previous prime is 656991553. The next prime is 656991623. The reversal of 656991589 is 985199656.

656991589 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 580569025 + 76422564 = 24095^2 + 8742^2 .

It is a cyclic number.

It is not a de Polignac number, because 656991589 - 2⁹ = 656991077 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 (656991509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328495794 + 328495795.

It is an arithmetic number, because the mean of its divisors is an integer number (328495795).

Almost surely, 2^656991589 is an apocalyptic number.

It is an amenable number.

656991589 is a deficient number, since it is larger than the sum of its proper divisors (1).

656991589 is an equidigital number, since it uses as much as digits as its factorization.

656991589 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5248800, while the sum is 58.

The square root of 656991589 is about 25631.8471632460. The cubic root of 656991589 is about 869.3338755369. Note that the first 3 decimals are identical.

The spelling of 656991589 in words is "six hundred fifty-six million, nine hundred ninety-one thousand, five hundred eighty-nine".