181688626138 has 8 divisors (see below), whose sum is σ = 273546073620. Its totient is φ = 90506601600.

The previous prime is 181688626121. The next prime is 181688626139. The reversal of 181688626138 is 831626886181.

It can be written as a sum of positive squares in 2 ways, for example, as 178267195089 + 3421431049 = 422217^2 + 58493^2 .

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

It is a super-3 number, since 3×181688626138³ (a number of 35 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (181688626139) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168855063 + ... + 168856138.

Almost surely, 2^181688626138 is an apocalyptic number.

181688626138 is a deficient number, since it is larger than the sum of its proper divisors (91857447482).

181688626138 is a wasteful number, since it uses less digits than its factorization.

181688626138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337711472.

The product of its digits is 5308416, while the sum is 58.

The spelling of 181688626138 in words is "one hundred eighty-one billion, six hundred eighty-eight million, six hundred twenty-six thousand, one hundred thirty-eight".