2100121022221 has 4 divisors (see below), whose sum is σ = 2100124359612. Its totient is φ = 2100117684832.

The previous prime is 2100121022213. The next prime is 2100121022243. The reversal of 2100121022221 is 1222201210012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 986821705321 + 1113299316900 = 993389^2 + 1055130^2 .

It is a cyclic number.

It is not a de Polignac number, because 2100121022221 - 2³ = 2100121022213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2100121022195 and 2100121022204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2100121022621) 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, 406600 + ... + 2089393.

It is an arithmetic number, because the mean of its divisors is an integer number (525031089903).

Almost surely, 2^{2100121022221} is an apocalyptic number.

It is an amenable number.

2100121022221 is a deficient number, since it is larger than the sum of its proper divisors (3337391).

2100121022221 is an equidigital number, since it uses as much as digits as its factorization.

2100121022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3337390.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 2100121022221 its reverse (1222201210012), we get a palindrome (3322322232233).

The spelling of 2100121022221 in words is "two trillion, one hundred billion, one hundred twenty-one million, twenty-two thousand, two hundred twenty-one".