681904589 has 2 divisors, whose sum is σ = 681904590. Its totient is φ = 681904588.

The previous prime is 681904541. The next prime is 681904603. The reversal of 681904589 is 985409186.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 493062025 + 188842564 = 22205^2 + 13742^2 .

It is a cyclic number.

It is not a de Polignac number, because 681904589 - 2²⁴ = 665127373 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 (681904789) 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, 340952294 + 340952295.

It is an arithmetic number, because the mean of its divisors is an integer number (340952295).

Almost surely, 2^681904589 is an apocalyptic number.

It is an amenable number.

681904589 is a deficient number, since it is larger than the sum of its proper divisors (1).

681904589 is an equidigital number, since it uses as much as digits as its factorization.

681904589 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 622080, while the sum is 50.

The square root of 681904589 is about 26113.3029125004. The cubic root of 681904589 is about 880.1861645568.

The spelling of 681904589 in words is "six hundred eighty-one million, nine hundred four thousand, five hundred eighty-nine".