2121101221 has 4 divisors (see below), whose sum is σ = 2121451552. Its totient is φ = 2120750892.

The previous prime is 2121101197. The next prime is 2121101261. The reversal of 2121101221 is 1221011212.

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 2121101221 - 2¹¹ = 2121099173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121101261) 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, 165921 + ... + 178246.

It is an arithmetic number, because the mean of its divisors is an integer number (530362888).

Almost surely, 2^2121101221 is an apocalyptic number.

It is an amenable number.

2121101221 is a deficient number, since it is larger than the sum of its proper divisors (350331).

2121101221 is an equidigital number, since it uses as much as digits as its factorization.

2121101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350330.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 2121101221 is about 46055.4146762354. The cubic root of 2121101221 is about 1284.8540505558.

Adding to 2121101221 its reverse (1221011212), we get a palindrome (3342112433).

Subtracting from 2121101221 its reverse (1221011212), we obtain a palindrome (900090009).

The spelling of 2121101221 in words is "two billion, one hundred twenty-one million, one hundred one thousand, two hundred twenty-one".