221343121 has 4 divisors (see below), whose sum is σ = 221678644. Its totient is φ = 221007600.

The previous prime is 221343113. The next prime is 221343127. The reversal of 221343121 is 121343122.

It is a happy number.

221343121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 141491025 + 79852096 = 11895^2 + 8936^2 .

It is a cyclic number.

It is not a de Polignac number, because 221343121 - 2³ = 221343113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221343127) 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, 166770 + ... + 168091.

It is an arithmetic number, because the mean of its divisors is an integer number (55419661).

Almost surely, 2^221343121 is an apocalyptic number.

It is an amenable number.

221343121 is a deficient number, since it is larger than the sum of its proper divisors (335523).

221343121 is an equidigital number, since it uses as much as digits as its factorization.

221343121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335522.

The product of its digits is 288, while the sum is 19.

The square root of 221343121 is about 14877.6046795175. The cubic root of 221343121 is about 604.9070922605.

Adding to 221343121 its reverse (121343122), we get a palindrome (342686243).

Subtracting from 221343121 its reverse (121343122), we obtain a palindrome (99999999).

The spelling of 221343121 in words is "two hundred twenty-one million, three hundred forty-three thousand, one hundred twenty-one".