21424221220 has 48 divisors (see below), whose sum is σ = 45734226048. Its totient is φ = 8429184000.

The previous prime is 21424221211. The next prime is 21424221223. The reversal of 21424221220 is 2212242412.

It is a junction number, because it is equal to n+sod(n) for n = 21424221191 and 21424221200.

It is not an unprimeable number, because it can be changed into a prime (21424221223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 282345 + ... + 350095.

It is an arithmetic number, because the mean of its divisors is an integer number (952796376).

Almost surely, 2^21424221220 is an apocalyptic number.

21424221220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21424221220 is an abundant number, since it is smaller than the sum of its proper divisors (24310004828).

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

21424221220 is a wasteful number, since it uses less digits than its factorization.

21424221220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68020 (or 68018 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

Adding to 21424221220 its reverse (2212242412), we get a palindrome (23636463632).

The spelling of 21424221220 in words is "twenty-one billion, four hundred twenty-four million, two hundred twenty-one thousand, two hundred twenty".