212121211121100 has 216 divisors, whose sum is σ = 671505128264880. Its totient is φ = 56002265280000.

The previous prime is 212121211121077. The next prime is 212121211121101. The reversal of 212121211121100 is 1121112121212.

It is a happy number.

212121211121100 is a `hidden beast` number, since 21 + 212 + 1 + 211 + 121 + 100 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (212121211121101) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1776217191 + ... + 1776336609.

Almost surely, 2^{212121211121100} is an apocalyptic number.

212121211121100 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 212121211121100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (335752564132440).

212121211121100 is an abundant number, since it is smaller than the sum of its proper divisors (459383917143780).

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

212121211121100 is a wasteful number, since it uses less digits than its factorization.

212121211121100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139081 (or 139071 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 212121211121100 its reverse (1121112121212), we get a palindrome (213242323242312).

The spelling of 212121211121100 in words is "two hundred twelve trillion, one hundred twenty-one billion, two hundred eleven million, one hundred twenty-one thousand, one hundred".