121121221 has 4 divisors (see below), whose sum is σ = 130438252. Its totient is φ = 111804192.

The previous prime is 121121213. The next prime is 121121227. The reversal of 121121221 is 122121121.

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 23328900 + 97792321 = 4830^2 + 9889^2 .

It is a cyclic number.

It is not a de Polignac number, because 121121221 - 2³ = 121121213 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 9317017 = 121121221 / (1 + 2 + 1 + 1 + 2 + 1 + 2 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121121227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4658496 + ... + 4658521.

It is an arithmetic number, because the mean of its divisors is an integer number (32609563).

Almost surely, 2^121121221 is an apocalyptic number.

It is an amenable number.

121121221 is a deficient number, since it is larger than the sum of its proper divisors (9317031).

121121221 is an equidigital number, since it uses as much as digits as its factorization.

121121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9317030.

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

The square root of 121121221 is about 11005.5086661181. The cubic root of 121121221 is about 494.7738599050.

Adding to 121121221 its reverse (122121121), we get a palindrome (243242342).

The spelling of 121121221 in words is "one hundred twenty-one million, one hundred twenty-one thousand, two hundred twenty-one".