318017221 has 2 divisors, whose sum is σ = 318017222. Its totient is φ = 318017220.

The previous prime is 318017209. The next prime is 318017237. The reversal of 318017221 is 122710813.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161417025 + 156600196 = 12705^2 + 12514^2 .

It is an emirp because it is prime and its reverse (122710813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 318017221 - 2¹⁹ = 317492933 is a prime.

It is a super-2 number, since 2×318017221² = 202269905705125682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (318017261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159008610 + 159008611.

It is an arithmetic number, because the mean of its divisors is an integer number (159008611).

Almost surely, 2^318017221 is an apocalyptic number.

It is an amenable number.

318017221 is a deficient number, since it is larger than the sum of its proper divisors (1).

318017221 is an equidigital number, since it uses as much as digits as its factorization.

318017221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 318017221 is about 17833.0373464534. The cubic root of 318017221 is about 682.5747406151.

The spelling of 318017221 in words is "three hundred eighteen million, seventeen thousand, two hundred twenty-one".