20320840 has 16 divisors (see below), whose sum is σ = 45721980. Its totient is φ = 8128320.

The previous prime is 20320837. The next prime is 20320847. The reversal of 20320840 is 4802302.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19061956 + 1258884 = 4366^2 + 1122^2 .

It is not an unprimeable number, because it can be changed into a prime (20320847) 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, 253971 + ... + 254050.

Almost surely, 2^20320840 is an apocalyptic number.

20320840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20320840 is an abundant number, since it is smaller than the sum of its proper divisors (25401140).

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

20320840 is a wasteful number, since it uses less digits than its factorization.

20320840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508032 (or 508028 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 20320840 is about 4507.8642393045. The cubic root of 20320840 is about 272.8855580830.

The spelling of 20320840 in words is "twenty million, three hundred twenty thousand, eight hundred forty".