168117138 has 72 divisors (see below), whose sum is σ = 434151900. Its totient is φ = 46851840.

The previous prime is 168117133. The next prime is 168117151. The reversal of 168117138 is 831711861.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 167883849 + 233289 = 12957^2 + 483^2 .

It is a super-2 number, since 2×168117138² = 56526744178622088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168117133) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 33838 + ... + 38486.

Almost surely, 2^168117138 is an apocalyptic number.

168117138 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 168117138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217075950).

168117138 is an abundant number, since it is smaller than the sum of its proper divisors (266034762).

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

168117138 is a wasteful number, since it uses less digits than its factorization.

168117138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4712 (or 4702 counting only the distinct ones).

The product of its digits is 8064, while the sum is 36.

The square root of 168117138 is about 12965.9993058769. Note that the first 3 decimals coincide. The cubic root of 168117138 is about 551.9130494739.

Adding to 168117138 its reverse (831711861), we get a palindrome (999828999).

The spelling of 168117138 in words is "one hundred sixty-eight million, one hundred seventeen thousand, one hundred thirty-eight".