21202144420 has 36 divisors (see below), whose sum is σ = 45292095324. Its totient is φ = 8337087040.

The previous prime is 21202144417. The next prime is 21202144421. The reversal of 21202144420 is 2444120212.

It can be written as a sum of positive squares in 2 ways, for example, as 4476412836 + 16725731584 = 66906^2 + 129328^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21202144391 and 21202144400.

It is not an unprimeable number, because it can be changed into a prime (21202144421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 82651 + ... + 221890.

It is an arithmetic number, because the mean of its divisors is an integer number (1258113759).

Almost surely, 2^21202144420 is an apocalyptic number.

21202144420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202144420 is an abundant number, since it is smaller than the sum of its proper divisors (24089950904).

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

21202144420 is a wasteful number, since it uses less digits than its factorization.

21202144420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304668 (or 304607 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

Adding to 21202144420 its reverse (2444120212), we get a palindrome (23646264632).

The spelling of 21202144420 in words is "twenty-one billion, two hundred two million, one hundred forty-four thousand, four hundred twenty".