318561493 has 2 divisors, whose sum is σ = 318561494. Its totient is φ = 318561492.

The previous prime is 318561461. The next prime is 318561517. The reversal of 318561493 is 394165813.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 265592209 + 52969284 = 16297^2 + 7278^2 .

It is an emirp because it is prime and its reverse (394165813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 318561493 - 2⁵ = 318561461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (318561403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159280746 + 159280747.

It is an arithmetic number, because the mean of its divisors is an integer number (159280747).

Almost surely, 2^318561493 is an apocalyptic number.

It is an amenable number.

318561493 is a deficient number, since it is larger than the sum of its proper divisors (1).

318561493 is an equidigital number, since it uses as much as digits as its factorization.

318561493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 40.

The square root of 318561493 is about 17848.2910386401. The cubic root of 318561493 is about 682.9639172144.

The spelling of 318561493 in words is "three hundred eighteen million, five hundred sixty-one thousand, four hundred ninety-three".