21211222220 has 48 divisors (see below), whose sum is σ = 45405813600. Its totient is φ = 8320406016.

The previous prime is 21211222217. The next prime is 21211222231. The reversal of 21211222220 is 2222211212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3228659 + ... + 3235221.

It is an arithmetic number, because the mean of its divisors is an integer number (945954450).

Almost surely, 2^21211222220 is an apocalyptic number.

21211222220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211222220 is an abundant number, since it is smaller than the sum of its proper divisors (24194591380).

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

21211222220 is a wasteful number, since it uses less digits than its factorization.

21211222220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9674 (or 9672 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21211222220 its reverse (2222211212), we get a palindrome (23433433432).

The spelling of 21211222220 in words is "twenty-one billion, two hundred eleven million, two hundred twenty-two thousand, two hundred twenty".