20021221100000 has 144 divisors (see below), whose sum is σ = 49627473544656. Its totient is φ = 7950026880000.

The previous prime is 20021221099969. The next prime is 20021221100003. The reversal of 20021221100000 is 112212002.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021221100003) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12969299 + ... + 14430701.

It is an arithmetic number, because the mean of its divisors is an integer number (344635232949).

Almost surely, 2^{20021221100000} is an apocalyptic number.

20021221100000 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 20021221100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24813736772328).

20021221100000 is an abundant number, since it is smaller than the sum of its proper divisors (29606252444656).

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

20021221100000 is an equidigital number, since it uses as much as digits as its factorization.

20021221100000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1461575 (or 1461547 counting only the distinct ones).

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

Adding to 20021221100000 its reverse (112212002), we get a palindrome (20021333312002).

The spelling of 20021221100000 in words is "twenty trillion, twenty-one billion, two hundred twenty-one million, one hundred thousand".