221634 has 24 divisors (see below), whose sum is σ = 549120. Its totient is φ = 63288.

The previous prime is 221623. The next prime is 221653. The reversal of 221634 is 436122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221634.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 754 + ... + 1005.

It is an arithmetic number, because the mean of its divisors is an integer number (22880).

2²²¹⁶³⁴ is an apocalyptic number.

221634 is the 252-nd nonagonal number.

221634 is an abundant number, since it is smaller than the sum of its proper divisors (327486).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221634 is a wasteful number, since it uses less digits than its factorization.

221634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1774 (or 1771 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 221634 is about 470.7802034920. The cubic root of 221634 is about 60.5171956676.

Adding to 221634 its reverse (436122), we get a palindrome (657756).

The spelling of 221634 in words is "two hundred twenty-one thousand, six hundred thirty-four".