201221200021000 has 128 divisors (see below), whose sum is σ = 491565219125760. Its totient is φ = 76952072736000.

The previous prime is 201221200020989. The next prime is 201221200021001. The reversal of 201221200021000 is 120002122102.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (201221200021001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45904990 + ... + 50097010.

It is an arithmetic number, because the mean of its divisors is an integer number (3840353274420).

Almost surely, 2^{201221200021000} is an apocalyptic number.

201221200021000 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 201221200021000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (245782609562880).

201221200021000 is an abundant number, since it is smaller than the sum of its proper divisors (290344019104760).

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

201221200021000 is a wasteful number, since it uses less digits than its factorization.

201221200021000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4194152 (or 4194138 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 201221200021000 its reverse (120002122102), we get a palindrome (201341202143102).

The spelling of 201221200021000 in words is "two hundred one trillion, two hundred twenty-one billion, two hundred million, twenty-one thousand".