21042404220 has 96 divisors (see below), whose sum is σ = 62044899840. Its totient is φ = 5318058240.

The previous prime is 21042404203. The next prime is 21042404231. The reversal of 21042404220 is 2240424012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 80475 + ... + 220365.

It is an arithmetic number, because the mean of its divisors is an integer number (646301040).

Almost surely, 2^21042404220 is an apocalyptic number.

21042404220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21042404220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31022449920).

21042404220 is an abundant number, since it is smaller than the sum of its proper divisors (41002495620).

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

21042404220 is a wasteful number, since it uses less digits than its factorization.

21042404220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140035 (or 140033 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 21.

Adding to 21042404220 its reverse (2240424012), we get a palindrome (23282828232).

The spelling of 21042404220 in words is "twenty-one billion, forty-two million, four hundred four thousand, two hundred twenty".