21224423220 has 384 divisors, whose sum is σ = 81957076992. Its totient is φ = 3960576000.

The previous prime is 21224423167. The next prime is 21224423237. The reversal of 21224423220 is 2232442212.

It is a super-2 number, since 2×21224423220² (a number of 21 digits) contains 22 as substring.

It is a congruent 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 127 ways as a sum of consecutive naturals, for example, 2217445 + ... + 2226995.

It is an arithmetic number, because the mean of its divisors is an integer number (213429888).

Almost surely, 2^21224423220 is an apocalyptic number.

21224423220 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 21224423220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40978538496).

21224423220 is an abundant number, since it is smaller than the sum of its proper divisors (60732653772).

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

21224423220 is a wasteful number, since it uses less digits than its factorization.

21224423220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9631 (or 9629 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 24.

Adding to 21224423220 its reverse (2232442212), we get a palindrome (23456865432).

It can be divided in two parts, 21224 and 423220, that added together give a palindrome (444444).

The spelling of 21224423220 in words is "twenty-one billion, two hundred twenty-four million, four hundred twenty-three thousand, two hundred twenty".