221789 has 4 divisors (see below), whose sum is σ = 231456. Its totient is φ = 212124.

The previous prime is 221773. The next prime is 221797. The reversal of 221789 is 987122.

It is a happy number.

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 221789 - 2⁴ = 221773 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221719) 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, 4799 + ... + 4844.

It is an arithmetic number, because the mean of its divisors is an integer number (57864).

221789 is a Friedman number, since it can be written as 7*(89*2)^2+1, using all its digits and the basic arithmetic operations.

2²²¹⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

221789 is a deficient number, since it is larger than the sum of its proper divisors (9667).

221789 is an equidigital number, since it uses as much as digits as its factorization.

221789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9666.

The product of its digits is 2016, while the sum is 29.

The square root of 221789 is about 470.9447950663. The cubic root of 221789 is about 60.5312999709.

The spelling of 221789 in words is "two hundred twenty-one thousand, seven hundred eighty-nine".