221329 has 4 divisors (see below), whose sum is σ = 230976. Its totient is φ = 211684.

The previous prime is 221327. The next prime is 221393. The reversal of 221329 is 923122.

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, and also an emirpimes, since its reverse is a distinct semiprime: 923122 = 2 ⋅461561.

It is a cyclic number.

It is not a de Polignac number, because 221329 - 2¹ = 221327 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221327) 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 3 ways as a sum of consecutive naturals, for example, 4789 + ... + 4834.

It is an arithmetic number, because the mean of its divisors is an integer number (57744).

2²²¹³²⁹ is an apocalyptic number.

It is an amenable number.

221329 is a deficient number, since it is larger than the sum of its proper divisors (9647).

221329 is an equidigital number, since it uses as much as digits as its factorization.

221329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9646.

The product of its digits is 216, while the sum is 19.

The square root of 221329 is about 470.4561616134. The cubic root of 221329 is about 60.4894228259.

The spelling of 221329 in words is "two hundred twenty-one thousand, three hundred twenty-nine".