809979901 has 4 divisors (see below), whose sum is σ = 810047232. Its totient is φ = 809912572.

The previous prime is 809979883. The next prime is 809979917. The reversal of 809979901 is 109979908.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 809979901 - 2²⁵ = 776425469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809979941) 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, 10141 + ... + 41506.

It is an arithmetic number, because the mean of its divisors is an integer number (202511808).

It is a 12030-hyperperfect number.

Almost surely, 2^809979901 is an apocalyptic number.

It is an amenable number.

809979901 is a deficient number, since it is larger than the sum of its proper divisors (67331).

809979901 is a wasteful number, since it uses less digits than its factorization.

809979901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67330.

The product of its (nonzero) digits is 367416, while the sum is 52.

The square root of 809979901 is about 28460.1458358878. The cubic root of 809979901 is about 932.1620415661.

The spelling of 809979901 in words is "eight hundred nine million, nine hundred seventy-nine thousand, nine hundred one".