20840020 has 12 divisors (see below), whose sum is σ = 43764084. Its totient is φ = 8336000.

The previous prime is 20839999. The next prime is 20840033. The reversal of 20840020 is 2004802.

It can be written as a sum of positive squares in 2 ways, for example, as 12988816 + 7851204 = 3604^2 + 2802^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20839976 and 20840003.

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, 520981 + ... + 521020.

It is an arithmetic number, because the mean of its divisors is an integer number (3647007).

Almost surely, 2^20840020 is an apocalyptic number.

20840020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20840020 is an abundant number, since it is smaller than the sum of its proper divisors (22924064).

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

20840020 is a wasteful number, since it uses less digits than its factorization.

20840020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1042010 (or 1042008 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 20840020 is about 4565.0870747446. The cubic root of 20840020 is about 275.1900394414.

Adding to 20840020 its reverse (2004802), we get a palindrome (22844822).

The spelling of 20840020 in words is "twenty million, eight hundred forty thousand, twenty".