20504840 has 16 divisors (see below), whose sum is σ = 46135980. Its totient is φ = 8201920.

The previous prime is 20504777. The next prime is 20504843. The reversal of 20504840 is 4840502.

It can be written as a sum of positive squares in 2 ways, for example, as 20484676 + 20164 = 4526^2 + 142^2 .

It is a super-3 number, since 3×20504840³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (20504843) 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, 256271 + ... + 256350.

Almost surely, 2^20504840 is an apocalyptic number.

20504840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20504840 is an abundant number, since it is smaller than the sum of its proper divisors (25631140).

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

20504840 is a wasteful number, since it uses less digits than its factorization.

20504840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512632 (or 512628 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 23.

The square root of 20504840 is about 4528.2270261108. The cubic root of 20504840 is about 273.7067208465.

The spelling of 20504840 in words is "twenty million, five hundred four thousand, eight hundred forty".