765681 has 24 divisors (see below), whose sum is σ = 1243584. Its totient is φ = 410400.

The previous prime is 765673. The next prime is 765707. The reversal of 765681 is 186567.

It is not a de Polignac number, because 765681 - 2³ = 765673 is a prime.

It is a super-2 number, since 2×765681² = 1172534787522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (765181) 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 in 23 ways as a sum of consecutive naturals, for example, 7531 + ... + 7631.

It is an arithmetic number, because the mean of its divisors is an integer number (51816).

765681 is a Friedman number, since it can be written as 7*(8+5^6*(6+1)), using all its digits and the basic arithmetic operations.

2⁷⁶⁵⁶⁸¹ is an apocalyptic number.

It is an amenable number.

765681 is a deficient number, since it is larger than the sum of its proper divisors (477903).

765681 is a wasteful number, since it uses less digits than its factorization.

765681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 130 counting only the distinct ones).

The product of its digits is 10080, while the sum is 33.

The square root of 765681 is about 875.0319994149. The cubic root of 765681 is about 91.4848731302.

The spelling of 765681 in words is "seven hundred sixty-five thousand, six hundred eighty-one".