2102121121021 has 4 divisors (see below), whose sum is σ = 2102126316192. Its totient is φ = 2102115925852.

The previous prime is 2102121121019. The next prime is 2102121121039. The reversal of 2102121121021 is 1201211212012.

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 2102121121021 - 2¹ = 2102121121019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2102121120986 and 2102121121004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2102121121091) 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, 1934161 + ... + 2818726.

It is an arithmetic number, because the mean of its divisors is an integer number (525531579048).

Almost surely, 2^{2102121121021} is an apocalyptic number.

It is an amenable number.

2102121121021 is a deficient number, since it is larger than the sum of its proper divisors (5195171).

2102121121021 is an equidigital number, since it uses as much as digits as its factorization.

2102121121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5195170.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 2102121121021 its reverse (1201211212012), we get a palindrome (3303332333033).

Subtracting from 2102121121021 its reverse (1201211212012), we obtain a palindrome (900909909009).

The spelling of 2102121121021 in words is "two trillion, one hundred two billion, one hundred twenty-one million, one hundred twenty-one thousand, twenty-one".