21122220210 has 128 divisors (see below), whose sum is σ = 62446325760. Its totient is φ = 4452662016.

The previous prime is 21122220191. The next prime is 21122220253. The reversal of 21122220210 is 1202222112.

It is a super-2 number, since 2×21122220210² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21122220210.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3980419 + ... + 3985721.

It is an arithmetic number, because the mean of its divisors is an integer number (487861920).

Almost surely, 2^21122220210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21122220210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31223162880).

21122220210 is an abundant number, since it is smaller than the sum of its proper divisors (41324105550).

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

21122220210 is a wasteful number, since it uses less digits than its factorization.

21122220210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6792.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21122220210 its reverse (1202222112), we get a palindrome (22324442322).

The spelling of 21122220210 in words is "twenty-one billion, one hundred twenty-two million, two hundred twenty thousand, two hundred ten".