221121 has 12 divisors (see below), whose sum is σ = 324480.
Its totient is φ = 145080.
The previous prime is 221101. The next prime is 221159. The reversal of 221121 is 121122.
It is a de Polignac number, because none of the positive numbers 2k-221121 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a Curzon number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (221101) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 556 + ... + 866.
It is an arithmetic number, because the mean of its divisors is an integer number (27040).
2221121 is an apocalyptic number.
It is an amenable number.
221121 is a deficient number, since it is larger than the sum of its proper divisors (103359).
221121 is a wasteful number, since it uses less digits than its factorization.
221121 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 396 (or 393 counting only the distinct ones).
The product of its digits is 8, while the sum is 9.
The square root of 221121 is about 470.2350476092.
The cubic root of 221121 is about 60.4704680220.
Adding to 221121 its reverse (121122), we get a palindrome (342243).
Subtracting from 221121 its reverse (121122), we obtain a palindrome (99999).
The spelling of 221121 in words is "two hundred twenty-one thousand, one hundred twenty-one", and thus it is an iban number.