2102111021 has 4 divisors (see below), whose sum is σ = 2103022944. Its totient is φ = 2101199100.

The previous prime is 2102111017. The next prime is 2102111071. The reversal of 2102111021 is 1201112012.

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 2102111021 - 2² = 2102111017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2102110993 and 2102111011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2102111071) 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 3 ways as a sum of consecutive naturals, for example, 452495 + ... + 457116.

It is an arithmetic number, because the mean of its divisors is an integer number (525755736).

Almost surely, 2^2102111021 is an apocalyptic number.

It is an amenable number.

2102111021 is a deficient number, since it is larger than the sum of its proper divisors (911923).

2102111021 is an equidigital number, since it uses as much as digits as its factorization.

2102111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 911922.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 2102111021 is about 45848.7842914073. The cubic root of 2102111021 is about 1281.0081212059.

Adding to 2102111021 its reverse (1201112012), we get a palindrome (3303223033).

Subtracting from 2102111021 its reverse (1201112012), we obtain a palindrome (900999009).

The spelling of 2102111021 in words is "two billion, one hundred two million, one hundred eleven thousand, twenty-one".