2101121221 has 4 divisors (see below), whose sum is σ = 2102425452. Its totient is φ = 2099816992.

The previous prime is 2101121207. The next prime is 2101121237. The reversal of 2101121221 is 1221211012.

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 823058721 + 1278062500 = 28689^2 + 35750^2 .

It is a cyclic number.

It is not a de Polignac number, because 2101121221 - 2⁹ = 2101120709 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 (2101121291) 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, 649696 + ... + 652921.

It is an arithmetic number, because the mean of its divisors is an integer number (525606363).

Almost surely, 2^2101121221 is an apocalyptic number.

It is an amenable number.

2101121221 is a deficient number, since it is larger than the sum of its proper divisors (1304231).

2101121221 is a wasteful number, since it uses less digits than its factorization.

2101121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1304230.

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

The square root of 2101121221 is about 45837.9888411348. The cubic root of 2101121221 is about 1280.8070311453.

Adding to 2101121221 its reverse (1221211012), we get a palindrome (3322332233).

The spelling of 2101121221 in words is "two billion, one hundred one million, one hundred twenty-one thousand, two hundred twenty-one".