221863 has 4 divisors (see below), whose sum is σ = 233560. Its totient is φ = 210168.

The previous prime is 221849. The next prime is 221873. The reversal of 221863 is 368122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221863 - 2⁵ = 221831 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221813) 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, 5820 + ... + 5857.

It is an arithmetic number, because the mean of its divisors is an integer number (58390).

2²²¹⁸⁶³ is an apocalyptic number.

221863 is a deficient number, since it is larger than the sum of its proper divisors (11697).

221863 is a wasteful number, since it uses less digits than its factorization.

221863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11696.

The product of its digits is 576, while the sum is 22.

The square root of 221863 is about 471.0233539858. The cubic root of 221863 is about 60.5380313209.

Subtracting from 221863 its sum of digits (22), we obtain a square (221841 = 471²).

Adding to 221863 its reverse (368122), we get a palindrome (589985).

The spelling of 221863 in words is "two hundred twenty-one thousand, eight hundred sixty-three".