318731993 has 8 divisors (see below), whose sum is σ = 325215936. Its totient is φ = 312303600.

The previous prime is 318731951. The next prime is 318732017. The reversal of 318731993 is 399137813.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 318731993 - 2¹⁶ = 318666457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (318731923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2198 + ... + 25343.

It is an arithmetic number, because the mean of its divisors is an integer number (40651992).

Almost surely, 2^318731993 is an apocalyptic number.

It is an amenable number.

318731993 is a deficient number, since it is larger than the sum of its proper divisors (6483943).

318731993 is a wasteful number, since it uses less digits than its factorization.

318731993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27775.

The product of its digits is 122472, while the sum is 44.

The square root of 318731993 is about 17853.0667673652. The cubic root of 318731993 is about 683.0857404543.

The spelling of 318731993 in words is "three hundred eighteen million, seven hundred thirty-one thousand, nine hundred ninety-three".