221764 has 6 divisors (see below), whose sum is σ = 388094. Its totient is φ = 110880.

The previous prime is 221747. The next prime is 221773. The reversal of 221764 is 467122.

It can be written as a sum of positive squares in only one way, i.e., 184900 + 36864 = 430^2 + 192^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27717 + ... + 27724.

2²²¹⁷⁶⁴ is an apocalyptic number.

It is an amenable number.

221764 is a deficient number, since it is larger than the sum of its proper divisors (166330).

221764 is a wasteful number, since it uses less digits than its factorization.

221764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55445 (or 55443 counting only the distinct ones).

The product of its digits is 672, while the sum is 22.

The square root of 221764 is about 470.9182519291. The cubic root of 221764 is about 60.5290255279.

Adding to 221764 its reverse (467122), we get a palindrome (688886).

The spelling of 221764 in words is "two hundred twenty-one thousand, seven hundred sixty-four".