20644420 has 12 divisors (see below), whose sum is σ = 43353324. Its totient is φ = 8257760.

The previous prime is 20644399. The next prime is 20644447. The reversal of 20644420 is 2444602.

It can be written as a sum of positive squares in 2 ways, for example, as 11930116 + 8714304 = 3454^2 + 2952^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20644391 and 20644400.

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, 516091 + ... + 516130.

It is an arithmetic number, because the mean of its divisors is an integer number (3612777).

Almost surely, 2^20644420 is an apocalyptic number.

20644420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20644420 is an abundant number, since it is smaller than the sum of its proper divisors (22708904).

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

20644420 is a wasteful number, since it uses less digits than its factorization.

20644420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1032230 (or 1032228 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

The square root of 20644420 is about 4543.6130997258. The cubic root of 20644420 is about 274.3263733025.

The spelling of 20644420 in words is "twenty million, six hundred forty-four thousand, four hundred twenty".