171221 has 4 divisors (see below), whose sum is σ = 174912. Its totient is φ = 167532.

The previous prime is 171203. The next prime is 171233. The reversal of 171221 is 122171.

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 171221 - 2¹⁰ = 170197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 171196 and 171205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (171251) 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, 1775 + ... + 1868.

It is an arithmetic number, because the mean of its divisors is an integer number (43728).

2¹⁷¹²²¹ is an apocalyptic number.

It is an amenable number.

171221 is a deficient number, since it is larger than the sum of its proper divisors (3691).

171221 is an equidigital number, since it uses as much as digits as its factorization.

171221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3690.

The product of its digits is 28, while the sum is 14.

The square root of 171221 is about 413.7885933662. The cubic root of 171221 is about 55.5288922423.

Adding to 171221 its reverse (122171), we get a palindrome (293392).

The spelling of 171221 in words is "one hundred seventy-one thousand, two hundred twenty-one", and thus it is an iban number.