766789921 has 2 divisors, whose sum is σ = 766789922. Its totient is φ = 766789920.

The previous prime is 766789873. The next prime is 766789931. The reversal of 766789921 is 129987667.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 709636321 + 57153600 = 26639^2 + 7560^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-766789921 is a prime.

It is not a weakly prime, because it can be changed into another prime (766789931) 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 as a sum of consecutive naturals, namely, 383394960 + 383394961.

It is an arithmetic number, because the mean of its divisors is an integer number (383394961).

Almost surely, 2^766789921 is an apocalyptic number.

It is an amenable number.

766789921 is a deficient number, since it is larger than the sum of its proper divisors (1).

766789921 is an equidigital number, since it uses as much as digits as its factorization.

766789921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2286144, while the sum is 55.

The square root of 766789921 is about 27690.9718319889. The cubic root of 766789921 is about 915.2901708418.

The spelling of 766789921 in words is "seven hundred sixty-six million, seven hundred eighty-nine thousand, nine hundred twenty-one".