765661 has 4 divisors (see below), whose sum is σ = 824572. Its totient is φ = 706752.

The previous prime is 765659. The next prime is 765673. The reversal of 765661 is 166567.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 109561 + 656100 = 331^2 + 810^2 .

It is a cyclic number.

It is not a de Polignac number, because 765661 - 2¹ = 765659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (765461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29436 + ... + 29461.

It is an arithmetic number, because the mean of its divisors is an integer number (206143).

2⁷⁶⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

765661 is a deficient number, since it is larger than the sum of its proper divisors (58911).

765661 is a wasteful number, since it uses less digits than its factorization.

765661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58910.

The product of its digits is 7560, while the sum is 31.

The square root of 765661 is about 875.0205711868. The cubic root of 765661 is about 91.4840765785.

It can be divided in two parts, 76566 and 1, that added together give a palindrome (76567).

The spelling of 765661 in words is "seven hundred sixty-five thousand, six hundred sixty-one".