20101111100021 has 4 divisors (see below), whose sum is σ = 22972698400032. Its totient is φ = 17229523800012.

The previous prime is 20101111099921. The next prime is 20101111100047. The reversal of 20101111100021 is 12000111110102.

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 20101111100021 - 2¹⁴ = 20101111083637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20101111099975 and 20101111100011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101111105021) 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, 1435793649995 + ... + 1435793650008.

It is an arithmetic number, because the mean of its divisors is an integer number (5743174600008).

Almost surely, 2^{20101111100021} is an apocalyptic number.

It is an amenable number.

20101111100021 is a deficient number, since it is larger than the sum of its proper divisors (2871587300011).

20101111100021 is an equidigital number, since it uses as much as digits as its factorization.

20101111100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2871587300010.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 20101111100021 its reverse (12000111110102), we get a palindrome (32101222210123).

The spelling of 20101111100021 in words is "twenty trillion, one hundred one billion, one hundred eleven million, one hundred thousand, twenty-one".