764991 has 16 divisors (see below), whose sum is σ = 1173600. Its totient is φ = 491904.

The previous prime is 764989. The next prime is 764993. The reversal of 764991 is 199467.

764991 is a `hidden beast` number, since 7 + 649 + 9 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (764989) and next prime (764993).

It is not a de Polignac number, because 764991 - 2¹ = 764989 is a prime.

It is a super-2 number, since 2×764991² = 1170422460162, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 764991.

It is not an unprimeable number, because it can be changed into a prime (764993) 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 15 ways as a sum of consecutive naturals, for example, 295 + ... + 1271.

It is an arithmetic number, because the mean of its divisors is an integer number (73350).

2⁷⁶⁴⁹⁹¹ is an apocalyptic number.

764991 is a deficient number, since it is larger than the sum of its proper divisors (408609).

764991 is a wasteful number, since it uses less digits than its factorization.

764991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1015 (or 1009 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 764991 is about 874.6376392541. The cubic root of 764991 is about 91.4573840785.

The spelling of 764991 in words is "seven hundred sixty-four thousand, nine hundred ninety-one".