21021222220 has 48 divisors (see below), whose sum is σ = 44355780000. Its totient is φ = 8368335360.

The previous prime is 21021222179. The next prime is 21021222221. The reversal of 21021222220 is 2222212012.

It is a junction number, because it is equal to n+sod(n) for n = 21021222194 and 21021222203.

It is not an unprimeable number, because it can be changed into a prime (21021222221) 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, 6006031 + ... + 6009529.

It is an arithmetic number, because the mean of its divisors is an integer number (924078750).

Almost surely, 2^21021222220 is an apocalyptic number.

21021222220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021222220 is an abundant number, since it is smaller than the sum of its proper divisors (23334557780).

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

21021222220 is a wasteful number, since it uses less digits than its factorization.

21021222220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4858 (or 4856 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21021222220 its reverse (2222212012), we get a palindrome (23243434232).

The spelling of 21021222220 in words is "twenty-one billion, twenty-one million, two hundred twenty-two thousand, two hundred twenty".