791561689 has 4 divisors (see below), whose sum is σ = 795935140. Its totient is φ = 787188240.

The previous prime is 791561677. The next prime is 791561713. The reversal of 791561689 is 986165197.

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

It can be written as a sum of positive squares in 2 ways, for example, as 101606400 + 689955289 = 10080^2 + 26267^2 .

It is a cyclic number.

It is not a de Polignac number, because 791561689 - 2²³ = 783173081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (791561669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2186454 + ... + 2186815.

It is an arithmetic number, because the mean of its divisors is an integer number (198983785).

Almost surely, 2^791561689 is an apocalyptic number.

It is an amenable number.

791561689 is a deficient number, since it is larger than the sum of its proper divisors (4373451).

791561689 is a wasteful number, since it uses less digits than its factorization.

791561689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4373450.

The product of its digits is 816480, while the sum is 52.

The square root of 791561689 is about 28134.7061296186. The cubic root of 791561689 is about 925.0422922957.

The spelling of 791561689 in words is "seven hundred ninety-one million, five hundred sixty-one thousand, six hundred eighty-nine".