20211221100000 has 864 divisors, whose sum is σ = 77910062624352. Its totient is φ = 4573632000000.

The previous prime is 20211221099981. The next prime is 20211221100121. The reversal of 20211221100000 is 112211202.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1484693194 + ... + 1484706806.

It is an arithmetic number, because the mean of its divisors is an integer number (90173683593).

Almost surely, 2^{20211221100000} is an apocalyptic number.

20211221100000 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 20211221100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38955031312176).

20211221100000 is an abundant number, since it is smaller than the sum of its proper divisors (57698841524352).

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

20211221100000 is a wasteful number, since it uses less digits than its factorization.

20211221100000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13766 (or 13731 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 20211221100000 its reverse (112211202), we get a palindrome (20211333311202).

The spelling of 20211221100000 in words is "twenty trillion, two hundred eleven billion, two hundred twenty-one million, one hundred thousand".