21221002122222 has 128 divisors (see below), whose sum is σ = 51304395571200. Its totient is φ = 5716382512896.

The previous prime is 21221002122217. The next prime is 21221002122227. The reversal of 21221002122222 is 22222120012212.

It is an interprime number because it is at equal distance from previous prime (21221002122217) and next prime (21221002122227).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221002122227) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 140207178 + ... + 140358450.

It is an arithmetic number, because the mean of its divisors is an integer number (400815590400).

Almost surely, 2^{21221002122222} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221002122222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25652197785600).

21221002122222 is an abundant number, since it is smaller than the sum of its proper divisors (30083393448978).

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

21221002122222 is a wasteful number, since it uses less digits than its factorization.

21221002122222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152150.

The product of its (nonzero) digits is 512, while the sum is 21.

Adding to 21221002122222 its reverse (22222120012212), we get a palindrome (43443122134434).

The spelling of 21221002122222 in words is "twenty-one trillion, two hundred twenty-one billion, two million, one hundred twenty-two thousand, two hundred twenty-two".