20021221000000 has 196 divisors, whose sum is σ = 54176077787328. Its totient is φ = 7280440000000.

The previous prime is 20021220999961. The next prime is 20021221000013. The reversal of 20021221000000 is 12212002.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 10089945 + ... + 11910055.

Almost surely, 2^{20021221000000} is an apocalyptic number.

20021221000000 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 20021221000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27088038893664).

20021221000000 is an abundant number, since it is smaller than the sum of its proper divisors (34154856787328).

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

20021221000000 is an frugal number, since it uses more digits than its factorization.

20021221000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1820164 (or 1820129 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 20021221000000 its reverse (12212002), we get a palindrome (20021233212002).

It can be divided in two parts, 200212 and 21000000, that added together give a palindrome (21200212).

The spelling of 20021221000000 in words is "twenty trillion, twenty-one billion, two hundred twenty-one million", and thus it is an aban number.