187281 has 6 divisors (see below), whose sum is σ = 270530. Its totient is φ = 124848.

The previous prime is 187277. The next prime is 187303. The reversal of 187281 is 182781.

It can be written as a sum of positive squares in only one way, i.e., 140625 + 46656 = 375^2 + 216^2 .

It is not a de Polignac number, because 187281 - 2² = 187277 is a prime.

It is a super-2 number, since 2×187281² = 70148345922, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

187281 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 187281.

It is not an unprimeable number, because it can be changed into a prime (187211) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10396 + ... + 10413.

2¹⁸⁷²⁸¹ is an apocalyptic number.

It is an amenable number.

187281 is a deficient number, since it is larger than the sum of its proper divisors (83249).

187281 is a wasteful number, since it uses less digits than its factorization.

187281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20815 (or 20812 counting only the distinct ones).

The product of its digits is 896, while the sum is 27.

The square root of 187281 is about 432.7597485904. The cubic root of 187281 is about 57.2134196756.

It can be divided in two parts, 1872 and 81, that added together give a triangular number (1953 = T₆₂).

The spelling of 187281 in words is "one hundred eighty-seven thousand, two hundred eighty-one".