21044200420 has 24 divisors (see below), whose sum is σ = 44630377848. Its totient is φ = 8334336000.

The previous prime is 21044200399. The next prime is 21044200423. The reversal of 21044200420 is 2400244012.

It can be written as a sum of positive squares in 4 ways, for example, as 9521466084 + 11522734336 = 97578^2 + 107344^2 .

It is not an unprimeable number, because it can be changed into a prime (21044200423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5206941 + ... + 5210980.

It is an arithmetic number, because the mean of its divisors is an integer number (1859599077).

Almost surely, 2^21044200420 is an apocalyptic number.

21044200420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21044200420 is an abundant number, since it is smaller than the sum of its proper divisors (23586177428).

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

21044200420 is a wasteful number, since it uses less digits than its factorization.

21044200420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10418031 (or 10418029 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

Adding to 21044200420 its reverse (2400244012), we get a palindrome (23444444432).

The spelling of 21044200420 in words is "twenty-one billion, forty-four million, two hundred thousand, four hundred twenty".