187681 has 4 divisors (see below), whose sum is σ = 202132. Its totient is φ = 173232.

The previous prime is 187669. The next prime is 187687. The reversal of 187681 is 186781.

187681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186781 = 7 ⋅26683.

It can be written as a sum of positive squares in 2 ways, for example, as 58081 + 129600 = 241^2 + 360^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-187681 is a prime.

It is a super-2 number, since 2×187681² = 70448315522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (187687) 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, 7206 + ... + 7231.

It is an arithmetic number, because the mean of its divisors is an integer number (50533).

2¹⁸⁷⁶⁸¹ is an apocalyptic number.

It is an amenable number.

187681 is a deficient number, since it is larger than the sum of its proper divisors (14451).

187681 is a wasteful number, since it uses less digits than its factorization.

187681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14450.

The product of its digits is 2688, while the sum is 31.

The square root of 187681 is about 433.2216522751. The cubic root of 187681 is about 57.2541233849.

Subtracting from 187681 its reverse (186781), we obtain a square (900 = 30²).

It can be divided in two parts, 18768 and 1, that added together give a square (18769 = 137²).

The spelling of 187681 in words is "one hundred eighty-seven thousand, six hundred eighty-one".