20001221012000 has 96 divisors (see below), whose sum is σ = 49157348660784. Its totient is φ = 7998152448000.

The previous prime is 20001221011901. The next prime is 20001221012021. The reversal of 20001221012000 is 21012210002.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 76531902736 + 19924689109264 = 276644^2 + 4463708^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13003730 + ... + 14460270.

Almost surely, 2^{20001221012000} is an apocalyptic number.

20001221012000 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 20001221012000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24578674330392).

20001221012000 is an abundant number, since it is smaller than the sum of its proper divisors (29156127648784).

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

20001221012000 is a wasteful number, since it uses less digits than its factorization.

20001221012000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1459999 (or 1459981 counting only the distinct ones).

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

Adding to 20001221012000 its reverse (21012210002), we get a palindrome (20022233222002).

The spelling of 20001221012000 in words is "twenty trillion, one billion, two hundred twenty-one million, twelve thousand".