181316538 has 24 divisors (see below), whose sum is σ = 423072468. Its totient is φ = 55789632.

The previous prime is 181316537. The next prime is 181316549. The reversal of 181316538 is 835613181.

It can be written as a sum of positive squares in 2 ways, for example, as 177502329 + 3814209 = 13323^2 + 1953^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (181316533) 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 11 ways as a sum of consecutive naturals, for example, 387195 + ... + 387662.

Almost surely, 2^181316538 is an apocalyptic number.

181316538 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

181316538 is an abundant number, since it is smaller than the sum of its proper divisors (241755930).

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

181316538 is a wasteful number, since it uses less digits than its factorization.

181316538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 774878 (or 774875 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 181316538 is about 13465.3829503657. The cubic root of 181316538 is about 565.9948411089.

The spelling of 181316538 in words is "one hundred eighty-one million, three hundred sixteen thousand, five hundred thirty-eight".