221543 has 4 divisors (see below), whose sum is σ = 253200. Its totient is φ = 189888.

The previous prime is 221539. The next prime is 221549. The reversal of 221543 is 345122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 345122 = 2 ⋅172561.

It is a cyclic number.

It is not a de Polignac number, because 221543 - 2² = 221539 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221549) 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, 15818 + ... + 15831.

It is an arithmetic number, because the mean of its divisors is an integer number (63300).

2²²¹⁵⁴³ is an apocalyptic number.

221543 is a deficient number, since it is larger than the sum of its proper divisors (31657).

221543 is an equidigital number, since it uses as much as digits as its factorization.

221543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31656.

The product of its digits is 240, while the sum is 17.

The square root of 221543 is about 470.6835454953. The cubic root of 221543 is about 60.5089120127.

Adding to 221543 its reverse (345122), we get a palindrome (566665).

The spelling of 221543 in words is "two hundred twenty-one thousand, five hundred forty-three".