21204143420 has 12 divisors (see below), whose sum is σ = 44528701224. Its totient is φ = 8481657360.

The previous prime is 21204143407. The next prime is 21204143447. The reversal of 21204143420 is 2434140212.

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, 530103566 + ... + 530103605.

It is an arithmetic number, because the mean of its divisors is an integer number (3710725102).

Almost surely, 2^21204143420 is an apocalyptic number.

21204143420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21204143420 is an abundant number, since it is smaller than the sum of its proper divisors (23324557804).

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

21204143420 is a wasteful number, since it uses less digits than its factorization.

21204143420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1060207180 (or 1060207178 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21204143420 its reverse (2434140212), we get a palindrome (23638283632).

The spelling of 21204143420 in words is "twenty-one billion, two hundred four million, one hundred forty-three thousand, four hundred twenty".