2001121000000 has 392 divisors, whose sum is σ = 5357208145608. Its totient is φ = 738816000000.

The previous prime is 2001120999979. The next prime is 2001121000009. The reversal of 2001121000000 is 1211002.

It can be written as a sum of positive squares in 28 ways, for example, as 1598424146944 + 402696853056 = 1264288^2 + 634584^2 .

It is not an unprimeable number, because it can be changed into a prime (2001121000009) by changing a digit.

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 55 ways as a sum of consecutive naturals, for example, 900998890 + ... + 901001110.

Almost surely, 2^{2001121000000} is an apocalyptic number.

2001121000000 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 2001121000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2678604072804).

2001121000000 is an abundant number, since it is smaller than the sum of its proper divisors (3356087145608).

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

2001121000000 is an frugal number, since it uses more digits than its factorization.

2001121000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2333 (or 2298 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 2001121000000 its reverse (1211002), we get a palindrome (2001122211002).

The spelling of 2001121000000 in words is "two trillion, one billion, one hundred twenty-one million", and thus it is an aban number.