20001221300000 has 144 divisors (see below), whose sum is σ = 50265821531520. Its totient is φ = 7830263520000.

The previous prime is 20001221299981. The next prime is 20001221300033. The reversal of 20001221300000 is 312210002.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2572211 + ... + 6827789.

It is an arithmetic number, because the mean of its divisors is an integer number (349068205080).

Almost surely, 2^{20001221300000} is an apocalyptic number.

20001221300000 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 20001221300000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25132910765760).

20001221300000 is an abundant number, since it is smaller than the sum of its proper divisors (30264600231520).

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

20001221300000 is an frugal number, since it uses more digits than its factorization.

20001221300000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4255661 (or 4255633 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

Adding to 20001221300000 its reverse (312210002), we get a palindrome (20001533510002).

The spelling of 20001221300000 in words is "twenty trillion, one billion, two hundred twenty-one million, three hundred thousand".