765116721 has 12 divisors (see below), whose sum is σ = 1105453440. Its totient is φ = 509946360.

The previous prime is 765116711. The next prime is 765116731. The reversal of 765116721 is 127611567.

765116721 is a `hidden beast` number, since 76 + 511 + 6 + 72 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (765116711) and next prime (765116731).

It is not a de Polignac number, because 765116721 - 2¹⁰ = 765115697 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (765116701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36916 + ... + 53786.

It is an arithmetic number, because the mean of its divisors is an integer number (92121120).

Almost surely, 2^765116721 is an apocalyptic number.

It is an amenable number.

765116721 is a deficient number, since it is larger than the sum of its proper divisors (340336719).

765116721 is a wasteful number, since it uses less digits than its factorization.

765116721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21916 (or 21913 counting only the distinct ones).

The product of its digits is 17640, while the sum is 36.

The square root of 765116721 is about 27660.7433197302. The cubic root of 765116721 is about 914.6239393436.

The spelling of 765116721 in words is "seven hundred sixty-five million, one hundred sixteen thousand, seven hundred twenty-one".