221181 has 4 divisors (see below), whose sum is σ = 294912. Its totient is φ = 147452.

The previous prime is 221173. The next prime is 221197. The reversal of 221181 is 181122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221181 - 2³ = 221173 is a prime.

It is a super-2 number, since 2×221181² = 97842069522, which contains 22 as substring.

It is a D-number.

It is a Curzon number.

221181 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 221181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221101) 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, 36861 + ... + 36866.

It is an arithmetic number, because the mean of its divisors is an integer number (73728).

2²²¹¹⁸¹ is an apocalyptic number.

It is an amenable number.

221181 is a deficient number, since it is larger than the sum of its proper divisors (73731).

221181 is an equidigital number, since it uses as much as digits as its factorization.

221181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73730.

The product of its digits is 32, while the sum is 15.

The square root of 221181 is about 470.2988411638. The cubic root of 221181 is about 60.4759369734.

The spelling of 221181 in words is "two hundred twenty-one thousand, one hundred eighty-one".