287138 has 4 divisors (see below), whose sum is σ = 430710. Its totient is φ = 143568.

The previous prime is 287137. The next prime is 287141. The reversal of 287138 is 831782.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 277729 + 9409 = 527^2 + 97^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 287138.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 71783 + ... + 71786.

2²⁸⁷¹³⁸ is an apocalyptic number.

287138 is a deficient number, since it is larger than the sum of its proper divisors (143572).

287138 is a wasteful number, since it uses less digits than its factorization.

287138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143571.

The product of its digits is 2688, while the sum is 29.

The square root of 287138 is about 535.8525916705. The cubic root of 287138 is about 65.9725934572.

Subtracting 287138 from its reverse (831782), we obtain a square (544644 = 738²).

The spelling of 287138 in words is "two hundred eighty-seven thousand, one hundred thirty-eight".