221663 has 12 divisors (see below), whose sum is σ = 257880. Its totient is φ = 189312.

The previous prime is 221659. The next prime is 221671. The reversal of 221663 is 366122.

It is not a de Polignac number, because 221663 - 2² = 221659 is a prime.

It is a Duffinian number.

221663 is a modest number, since divided by 663 gives 221 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221603) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3728 + ... + 3786.

It is an arithmetic number, because the mean of its divisors is an integer number (21490).

2²²¹⁶⁶³ is an apocalyptic number.

221663 is a deficient number, since it is larger than the sum of its proper divisors (36217).

221663 is a wasteful number, since it uses less digits than its factorization.

221663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106 (or 89 counting only the distinct ones).

The product of its digits is 432, while the sum is 20.

The square root of 221663 is about 470.8110024203. The cubic root of 221663 is about 60.5198350372.

Adding to 221663 its reverse (366122), we get a palindrome (587785).

The spelling of 221663 in words is "two hundred twenty-one thousand, six hundred sixty-three".