20111021200021 has 4 divisors (see below), whose sum is σ = 20111281880544. Its totient is φ = 20110760519500.

The previous prime is 20111021199989. The next prime is 20111021200031. The reversal of 20111021200021 is 12000212011102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20111021200021 - 2⁵ = 20111021199989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20111021199974 and 20111021200010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111021200031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130224505 + ... + 130378846.

It is an arithmetic number, because the mean of its divisors is an integer number (5027820470136).

Almost surely, 2^{20111021200021} is an apocalyptic number.

It is an amenable number.

20111021200021 is a deficient number, since it is larger than the sum of its proper divisors (260680523).

20111021200021 is an equidigital number, since it uses as much as digits as its factorization.

20111021200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260680522.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 20111021200021 its reverse (12000212011102), we get a palindrome (32111233211123).

It can be divided in two parts, 2011102 and 1200021, that multiplied together give a palindrome (2413364633142).

The spelling of 20111021200021 in words is "twenty trillion, one hundred eleven billion, twenty-one million, two hundred thousand, twenty-one".