20121021200021 has 32 divisors (see below), whose sum is σ = 23737199247360. Its totient is φ = 16698609081216.

The previous prime is 20121021199997. The next prime is 20121021200041. The reversal of 20121021200021 is 12000212012102.

It is a cyclic number.

It is not a de Polignac number, because 20121021200021 - 2³⁸ = 19846143293077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121021199969 and 20121021200005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121021200041) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24913481 + ... + 25708433.

It is an arithmetic number, because the mean of its divisors is an integer number (741787476480).

Almost surely, 2^{20121021200021} is an apocalyptic number.

It is an amenable number.

20121021200021 is a deficient number, since it is larger than the sum of its proper divisors (3616178047339).

20121021200021 is a wasteful number, since it uses less digits than its factorization.

20121021200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 795833.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 20121021200021 its reverse (12000212012102), we get a palindrome (32121233212123).

It can be divided in two parts, 2012102 and 1200021, that multiplied together give a palindrome (2414564654142).

The spelling of 20121021200021 in words is "twenty trillion, one hundred twenty-one billion, twenty-one million, two hundred thousand, twenty-one".