840809020 has 12 divisors (see below), whose sum is σ = 1765698984. Its totient is φ = 336323600.

The previous prime is 840808993. The next prime is 840809027. The reversal of 840809020 is 20908048.

It is a super-2 number, since 2×840809020² = 1413919616226720800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840809027) 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, 21020206 + ... + 21020245.

It is an arithmetic number, because the mean of its divisors is an integer number (147141582).

Almost surely, 2^840809020 is an apocalyptic number.

It is an amenable number.

840809020 is an abundant number, since it is smaller than the sum of its proper divisors (924889964).

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

840809020 is a wasteful number, since it uses less digits than its factorization.

840809020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42040460 (or 42040458 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 840809020 is about 28996.7070544226. The cubic root of 840809020 is about 943.8416122636.

The spelling of 840809020 in words is "eight hundred forty million, eight hundred nine thousand, twenty".