221505 has 8 divisors (see below), whose sum is σ = 354432. Its totient is φ = 118128.

The previous prime is 221497. The next prime is 221509. The reversal of 221505 is 505122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 221505 - 2³ = 221497 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15), and also a Moran number because the ratio is a prime number: 14767 = 221505 / (2 + 2 + 1 + 5 + 0 + 5).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221509) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 7369 + ... + 7398.

It is an arithmetic number, because the mean of its divisors is an integer number (44304).

2²²¹⁵⁰⁵ is an apocalyptic number.

It is an amenable number.

221505 is a deficient number, since it is larger than the sum of its proper divisors (132927).

221505 is a wasteful number, since it uses less digits than its factorization.

221505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14775.

The product of its (nonzero) digits is 100, while the sum is 15.

The square root of 221505 is about 470.6431769398. The cubic root of 221505 is about 60.5054522327.

Adding to 221505 its reverse (505122), we get a palindrome (726627).

It can be divided in two parts, 22150 and 5, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 221505 in words is "two hundred twenty-one thousand, five hundred five".