681256789 has 2 divisors, whose sum is σ = 681256790. Its totient is φ = 681256788.

The previous prime is 681256781. The next prime is 681256801. The reversal of 681256789 is 987652186.

681256789 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 667343889 + 13912900 = 25833^2 + 3730^2 .

It is a cyclic number.

It is not a de Polignac number, because 681256789 - 2³ = 681256781 is a prime.

It is a super-2 number, since 2×681256789² = 928221625117181042, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681256781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340628394 + 340628395.

It is an arithmetic number, because the mean of its divisors is an integer number (340628395).

Almost surely, 2^681256789 is an apocalyptic number.

It is an amenable number.

681256789 is a deficient number, since it is larger than the sum of its proper divisors (1).

681256789 is an equidigital number, since it uses as much as digits as its factorization.

681256789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 52.

The square root of 681256789 is about 26100.8963256054. The cubic root of 681256789 is about 879.9073546579.

The spelling of 681256789 in words is "six hundred eighty-one million, two hundred fifty-six thousand, seven hundred eighty-nine".