21110111020021 has 4 divisors (see below), whose sum is σ = 21110120287200. Its totient is φ = 21110101752844.

The previous prime is 21110111019947. The next prime is 21110111020039. The reversal of 21110111020021 is 12002011101112.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21110111020021 - 2¹⁵ = 21110110987253 is a prime.

It is a super-2 number, since 2×21110111020021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21110111019983 and 21110111020010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110111020081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1416750 + ... + 6650368.

It is an arithmetic number, because the mean of its divisors is an integer number (5277530071800).

Almost surely, 2^{21110111020021} is an apocalyptic number.

It is an amenable number.

21110111020021 is a deficient number, since it is larger than the sum of its proper divisors (9267179).

21110111020021 is an equidigital number, since it uses as much as digits as its factorization.

21110111020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9267178.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21110111020021 its reverse (12002011101112), we get a palindrome (33112122121133).

The spelling of 21110111020021 in words is "twenty-one trillion, one hundred ten billion, one hundred eleven million, twenty thousand, twenty-one".