201220021100 has 72 divisors (see below), whose sum is σ = 499358539008. Its totient is φ = 68943700800.

The previous prime is 201220021073. The next prime is 201220021103. The reversal of 201220021100 is 1120022102.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (201220021103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 962579 + ... + 1152821.

It is an arithmetic number, because the mean of its divisors is an integer number (6935535264).

Almost surely, 2^201220021100 is an apocalyptic number.

201220021100 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 201220021100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (249679269504).

201220021100 is an abundant number, since it is smaller than the sum of its proper divisors (298138517908).

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

201220021100 is a wasteful number, since it uses less digits than its factorization.

201220021100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191775 (or 191768 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 201220021100 its reverse (1120022102), we get a palindrome (202340043202).

The spelling of 201220021100 in words is "two hundred one billion, two hundred twenty million, twenty-one thousand, one hundred".