691323779 has 4 divisors (see below), whose sum is σ = 715162560. Its totient is φ = 667485000.

The previous prime is 691323769. The next prime is 691323791. The reversal of 691323779 is 977323196.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 691323779 - 2²⁴ = 674546563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691323769) 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 3 ways as a sum of consecutive naturals, for example, 11919347 + ... + 11919404.

It is an arithmetic number, because the mean of its divisors is an integer number (178790640).

Almost surely, 2^691323779 is an apocalyptic number.

691323779 is a deficient number, since it is larger than the sum of its proper divisors (23838781).

691323779 is a wasteful number, since it uses less digits than its factorization.

691323779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23838780.

The product of its digits is 428652, while the sum is 47.

The square root of 691323779 is about 26293.0367017581. The cubic root of 691323779 is about 884.2203349650.

The spelling of 691323779 in words is "six hundred ninety-one million, three hundred twenty-three thousand, seven hundred seventy-nine".