221313121 has 16 divisors (see below), whose sum is σ = 240629760. Its totient is φ = 202849920.

The previous prime is 221313101. The next prime is 221313133. The reversal of 221313121 is 121313122.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221313121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221313095 and 221313104.

It is not an unprimeable number, because it can be changed into a prime (221313101) 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 15 ways as a sum of consecutive naturals, for example, 97815 + ... + 100051.

It is an arithmetic number, because the mean of its divisors is an integer number (15039360).

Almost surely, 2^221313121 is an apocalyptic number.

It is an amenable number.

221313121 is a deficient number, since it is larger than the sum of its proper divisors (19316639).

221313121 is a wasteful number, since it uses less digits than its factorization.

221313121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2424.

The product of its digits is 72, while the sum is 16.

The square root of 221313121 is about 14876.5964185361. The cubic root of 221313121 is about 604.8797620946.

Adding to 221313121 its reverse (121313122), we get a palindrome (342626243).

Subtracting from 221313121 its reverse (121313122), we obtain a palindrome (99999999).

It can be divided in two parts, 22131 and 3121, that added together give a palindrome (25252).

The spelling of 221313121 in words is "two hundred twenty-one million, three hundred thirteen thousand, one hundred twenty-one".