221843 has 4 divisors (see below), whose sum is σ = 223368. Its totient is φ = 220320.

The previous prime is 221831. The next prime is 221849. The reversal of 221843 is 348122.

221843 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, and also an emirpimes, since its reverse is a distinct semiprime: 348122 = 2 ⋅174061.

It is a cyclic number.

It is not a de Polignac number, because 221843 - 2⁴ = 221827 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (221849) 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, 518 + ... + 843.

It is an arithmetic number, because the mean of its divisors is an integer number (55842).

221843 is a Friedman number, since it can be written as (8^3-41)^2+2, using all its digits and the basic arithmetic operations.

2²²¹⁸⁴³ is an apocalyptic number.

221843 is a deficient number, since it is larger than the sum of its proper divisors (1525).

221843 is a wasteful number, since it uses less digits than its factorization.

221843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1524.

The product of its digits is 384, while the sum is 20.

The square root of 221843 is about 471.0021231375. The cubic root of 221843 is about 60.5362121847.

Adding to 221843 its reverse (348122), we get a palindrome (569965).

The spelling of 221843 in words is "two hundred twenty-one thousand, eight hundred forty-three".