221601 has 4 divisors (see below), whose sum is σ = 295472. Its totient is φ = 147732.

The previous prime is 221587. The next prime is 221603. The reversal of 221601 is 106122.

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 not a de Polignac number, because 221601 - 2⁶ = 221537 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221601.

It is not an unprimeable number, because it can be changed into a prime (221603) 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, 36931 + ... + 36936.

It is an arithmetic number, because the mean of its divisors is an integer number (73868).

2²²¹⁶⁰¹ is an apocalyptic number.

It is an amenable number.

221601 is a deficient number, since it is larger than the sum of its proper divisors (73871).

221601 is an equidigital number, since it uses as much as digits as its factorization.

221601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73870.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 221601 is about 470.7451539846. The cubic root of 221601 is about 60.5141919669.

Adding to 221601 its reverse (106122), we get a palindrome (327723).

The spelling of 221601 in words is "two hundred twenty-one thousand, six hundred one".