765606721 has 16 divisors (see below), whose sum is σ = 870248448. Its totient is φ = 667227600.

The previous prime is 765606719. The next prime is 765606733. The reversal of 765606721 is 127606567.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 765606721 - 2¹ = 765606719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (765606761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25996 + ... + 46978.

It is an arithmetic number, because the mean of its divisors is an integer number (54390528).

Almost surely, 2^765606721 is an apocalyptic number.

It is an amenable number.

765606721 is a deficient number, since it is larger than the sum of its proper divisors (104641727).

765606721 is a wasteful number, since it uses less digits than its factorization.

765606721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21132.

The product of its (nonzero) digits is 105840, while the sum is 40.

The square root of 765606721 is about 27669.5992200827. The cubic root of 765606721 is about 914.8191470724.

The spelling of 765606721 in words is "seven hundred sixty-five million, six hundred six thousand, seven hundred twenty-one".