79913809 has 4 divisors (see below), whose sum is σ = 79994020. Its totient is φ = 79833600.

The previous prime is 79913783. The next prime is 79913819. The reversal of 79913809 is 90831997.

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 47651409 + 32262400 = 6903^2 + 5680^2 .

It is a cyclic number.

It is not a de Polignac number, because 79913809 - 2⁵ = 79913777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79913819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38592 + ... + 40609.

It is an arithmetic number, because the mean of its divisors is an integer number (19998505).

Almost surely, 2^79913809 is an apocalyptic number.

It is an amenable number.

79913809 is a deficient number, since it is larger than the sum of its proper divisors (80211).

79913809 is a wasteful number, since it uses less digits than its factorization.

79913809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80210.

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 79913809 is about 8939.4523881500. The cubic root of 79913809 is about 430.7321383330.

The spelling of 79913809 in words is "seventy-nine million, nine hundred thirteen thousand, eight hundred nine".