21044440220 has 12 divisors (see below), whose sum is σ = 44193324504. Its totient is φ = 8417776080.

The previous prime is 21044440217. The next prime is 21044440253. The reversal of 21044440220 is 2204444012.

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 526110986 + ... + 526111025.

It is an arithmetic number, because the mean of its divisors is an integer number (3682777042).

Almost surely, 2^21044440220 is an apocalyptic number.

21044440220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21044440220 is an abundant number, since it is smaller than the sum of its proper divisors (23148884284).

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

21044440220 is a wasteful number, since it uses less digits than its factorization.

21044440220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1052222020 (or 1052222018 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 23.

Adding to 21044440220 its reverse (2204444012), we get a palindrome (23248884232).

The spelling of 21044440220 in words is "twenty-one billion, forty-four million, four hundred forty thousand, two hundred twenty".