21222122100 has 72 divisors (see below), whose sum is σ = 61493959968. Its totient is φ = 5650819200.

The previous prime is 21222122099. The next prime is 21222122191. The reversal of 21222122100 is 122122212.

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 21222122100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 150855 + ... + 255345.

Almost surely, 2^21222122100 is an apocalyptic number.

21222122100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21222122100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30746979984).

21222122100 is an abundant number, since it is smaller than the sum of its proper divisors (40271837868).

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

21222122100 is a wasteful number, since it uses less digits than its factorization.

21222122100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105185 (or 105178 counting only the distinct ones).

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

Adding to 21222122100 its reverse (122122212), we get a palindrome (21344244312).

The spelling of 21222122100 in words is "twenty-one billion, two hundred twenty-two million, one hundred twenty-two thousand, one hundred".