21055305220 has 24 divisors (see below), whose sum is σ = 44965569600. Its totient is φ = 8279373792.

The previous prime is 21055305191. The next prime is 21055305233. The reversal of 21055305220 is 2250355012.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8920560 + ... + 8922919.

It is an arithmetic number, because the mean of its divisors is an integer number (1873565400).

Almost surely, 2^21055305220 is an apocalyptic number.

21055305220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21055305220 is an abundant number, since it is smaller than the sum of its proper divisors (23910264380).

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

21055305220 is a wasteful number, since it uses less digits than its factorization.

21055305220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17843547 (or 17843545 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 25.

The spelling of 21055305220 in words is "twenty-one billion, fifty-five million, three hundred five thousand, two hundred twenty".