21044205020 has 12 divisors (see below), whose sum is σ = 44192830584. Its totient is φ = 8417682000.

The previous prime is 21044204957. The next prime is 21044205043. The reversal of 21044205020 is 2050244012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1052210251 = 21044205020 / (2 + 1 + 0 + 4 + 4 + 2 + 0 + 5 + 0 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 21044204983 and 21044205001.

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, 526105106 + ... + 526105145.

It is an arithmetic number, because the mean of its divisors is an integer number (3682735882).

Almost surely, 2^21044205020 is an apocalyptic number.

21044205020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21044205020 is an abundant number, since it is smaller than the sum of its proper divisors (23148625564).

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

21044205020 is a wasteful number, since it uses less digits than its factorization.

21044205020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1052210260 (or 1052210258 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

Adding to 21044205020 its reverse (2050244012), we get a palindrome (23094449032).

The spelling of 21044205020 in words is "twenty-one billion, forty-four million, two hundred five thousand, twenty".