221641 has 4 divisors (see below), whose sum is σ = 253312. Its totient is φ = 189972.

The previous prime is 221623. The next prime is 221653. The reversal of 221641 is 146122.

221641 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 146122 = 2 ⋅73061.

It is a cyclic number.

It is not a de Polignac number, because 221641 - 2¹³ = 213449 is a prime.

It is a Duffinian number.

221641 is a lucky number.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (221621) 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, 15825 + ... + 15838.

It is an arithmetic number, because the mean of its divisors is an integer number (63328).

2²²¹⁶⁴¹ is an apocalyptic number.

It is an amenable number.

221641 is a deficient number, since it is larger than the sum of its proper divisors (31671).

221641 is an equidigital number, since it uses as much as digits as its factorization.

221641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31670.

The product of its digits is 96, while the sum is 16.

The square root of 221641 is about 470.7876379006. The cubic root of 221641 is about 60.5178327779.

Adding to 221641 its reverse (146122), we get a palindrome (367763).

The spelling of 221641 in words is "two hundred twenty-one thousand, six hundred forty-one".