221212121200 has 120 divisors (see below), whose sum is σ = 607703925888. Its totient is φ = 75804368640.

The previous prime is 221212121177. The next prime is 221212121227. The reversal of 221212121200 is 2121212122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (16).

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, 5588679 + ... + 5628121.

Almost surely, 2^221212121200 is an apocalyptic number.

221212121200 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 221212121200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (303851962944).

221212121200 is an abundant number, since it is smaller than the sum of its proper divisors (386491804688).

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

221212121200 is a wasteful number, since it uses less digits than its factorization.

221212121200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41471 (or 41460 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 221212121200 its reverse (2121212122), we get a palindrome (223333333322).

The spelling of 221212121200 in words is "two hundred twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, two hundred".