318221 has 4 divisors (see below), whose sum is σ = 319872. Its totient is φ = 316572.

The previous prime is 318211. The next prime is 318229. The reversal of 318221 is 122813.

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: 122813 = 191 ⋅643.

It is a cyclic number.

It is not a de Polignac number, because 318221 - 2¹⁰ = 317197 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 318221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (318229) 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, 491 + ... + 936.

It is an arithmetic number, because the mean of its divisors is an integer number (79968).

2³¹⁸²²¹ is an apocalyptic number.

It is an amenable number.

318221 is a deficient number, since it is larger than the sum of its proper divisors (1651).

318221 is a wasteful number, since it uses less digits than its factorization.

318221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1650.

The product of its digits is 96, while the sum is 17.

The square root of 318221 is about 564.1108047184. The cubic root of 318221 is about 68.2720502846.

The spelling of 318221 in words is "three hundred eighteen thousand, two hundred twenty-one".