21242203220 has 48 divisors (see below), whose sum is σ = 50996107008. Its totient is φ = 7280924160.

The previous prime is 21242203207. The next prime is 21242203267. The reversal of 21242203220 is 2230224212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21242203192 and 21242203201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 506369 + ... + 546711.

It is an arithmetic number, because the mean of its divisors is an integer number (1062418896).

Almost surely, 2^21242203220 is an apocalyptic number.

21242203220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21242203220 is an abundant number, since it is smaller than the sum of its proper divisors (29753903788).

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

21242203220 is a wasteful number, since it uses less digits than its factorization.

21242203220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44120 (or 44118 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

Adding to 21242203220 its reverse (2230224212), we get a palindrome (23472427432).

The spelling of 21242203220 in words is "twenty-one billion, two hundred forty-two million, two hundred three thousand, two hundred twenty".