212121212221100 has 432 divisors, whose sum is σ = 582000715570176. Its totient is φ = 65677277952000.

The previous prime is 212121212221003. The next prime is 212121212221117. The reversal of 212121212221100 is 1122212121212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 16519050680 + ... + 16519063520.

Almost surely, 2^{212121212221100} is an apocalyptic number.

212121212221100 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 212121212221100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (291000357785088).

212121212221100 is an abundant number, since it is smaller than the sum of its proper divisors (369879503349076).

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

212121212221100 is a wasteful number, since it uses less digits than its factorization.

212121212221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15906 (or 15886 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 212121212221100 its reverse (1122212121212), we get a palindrome (213243424342312).

The spelling of 212121212221100 in words is "two hundred twelve trillion, one hundred twenty-one billion, two hundred twelve million, two hundred twenty-one thousand, one hundred".