21255605214220 has 24 divisors (see below), whose sum is σ = 48070368715824. Its totient is φ = 7848223463616.

The previous prime is 21255605214209. The next prime is 21255605214223. The reversal of 21255605214220 is 2241250655212.

It is a self number, because there is not a number n which added to its sum of digits gives 21255605214220.

It is not an unprimeable number, because it can be changed into a prime (21255605214223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40876163614 + ... + 40876164133.

It is an arithmetic number, because the mean of its divisors is an integer number (2002932029826).

Almost surely, 2^{21255605214220} is an apocalyptic number.

21255605214220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21255605214220 is an abundant number, since it is smaller than the sum of its proper divisors (26814763501604).

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

21255605214220 is a wasteful number, since it uses less digits than its factorization.

21255605214220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81752327769 (or 81752327767 counting only the distinct ones).

The product of its (nonzero) digits is 96000, while the sum is 37.

Adding to 21255605214220 its reverse (2241250655212), we get a palindrome (23496855869432).

The spelling of 21255605214220 in words is "twenty-one trillion, two hundred fifty-five billion, six hundred five million, two hundred fourteen thousand, two hundred twenty".