809861020 has 12 divisors (see below), whose sum is σ = 1700708184. Its totient is φ = 323944400.

The previous prime is 809860993. The next prime is 809861053. The reversal of 809861020 is 20168908.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20246506 + ... + 20246545.

It is an arithmetic number, because the mean of its divisors is an integer number (141725682).

Almost surely, 2^809861020 is an apocalyptic number.

It is an amenable number.

809861020 is an abundant number, since it is smaller than the sum of its proper divisors (890847164).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

809861020 is a wasteful number, since it uses less digits than its factorization.

809861020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40493060 (or 40493058 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 809861020 is about 28458.0572070547. The cubic root of 809861020 is about 932.1164347646.

The spelling of 809861020 in words is "eight hundred nine million, eight hundred sixty-one thousand, twenty".