21243333220 has 12 divisors (see below), whose sum is σ = 44610999804. Its totient is φ = 8497333280.

The previous prime is 21243333197. The next prime is 21243333247. The reversal of 21243333220 is 2233334212.

It can be written as a sum of positive squares in 2 ways, for example, as 3297515776 + 17945817444 = 57424^2 + 133962^2 .

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, 531083311 + ... + 531083350.

It is an arithmetic number, because the mean of its divisors is an integer number (3717583317).

Almost surely, 2^21243333220 is an apocalyptic number.

21243333220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21243333220 is an abundant number, since it is smaller than the sum of its proper divisors (23367666584).

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

21243333220 is a wasteful number, since it uses less digits than its factorization.

21243333220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1062166670 (or 1062166668 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 25.

Adding to 21243333220 its reverse (2233334212), we get a palindrome (23476667432).

The spelling of 21243333220 in words is "twenty-one billion, two hundred forty-three million, three hundred thirty-three thousand, two hundred twenty".