917221 has 4 divisors (see below), whose sum is σ = 925452. Its totient is φ = 908992.

The previous prime is 917219. The next prime is 917227. The reversal of 917221 is 122719.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 376996 + 540225 = 614^2 + 735^2 .

It is a cyclic number.

It is not a de Polignac number, because 917221 - 2¹ = 917219 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 917192 and 917201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (917227) 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, 3946 + ... + 4171.

It is an arithmetic number, because the mean of its divisors is an integer number (231363).

2⁹¹⁷²²¹ is an apocalyptic number.

It is an amenable number.

917221 is a deficient number, since it is larger than the sum of its proper divisors (8231).

917221 is a wasteful number, since it uses less digits than its factorization.

917221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8230.

The product of its digits is 252, while the sum is 22.

The square root of 917221 is about 957.7165551456. The cubic root of 917221 is about 97.1608554351.

The spelling of 917221 in words is "nine hundred seventeen thousand, two hundred twenty-one".