318687138 has 72 divisors (see below), whose sum is σ = 867432384. Its totient is φ = 82771920.

The previous prime is 318687113. The next prime is 318687139. The reversal of 318687138 is 831786813.

It is a super-2 number, since 2×318687138² = 203122983853262088, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 318687093 and 318687102.

It is not an unprimeable number, because it can be changed into a prime (318687139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4795 + ... + 25697.

It is an arithmetic number, because the mean of its divisors is an integer number (12047672).

Almost surely, 2^318687138 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 318687138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (433716192).

318687138 is an abundant number, since it is smaller than the sum of its proper divisors (548745246).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

318687138 is a wasteful number, since it uses less digits than its factorization.

318687138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20940 (or 20926 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 318687138 is about 17851.8104964174. The cubic root of 318687138 is about 683.0536955085.

The spelling of 318687138 in words is "three hundred eighteen million, six hundred eighty-seven thousand, one hundred thirty-eight".