81287 has 4 divisors (see below), whose sum is σ = 84120. Its totient is φ = 78456.

The previous prime is 81283. The next prime is 81293. The reversal of 81287 is 78218.

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

It is a cyclic number.

It is not a de Polignac number, because 81287 - 2² = 81283 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81287.

It is not an unprimeable number, because it can be changed into a prime (81281) 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, 1373 + ... + 1430.

It is an arithmetic number, because the mean of its divisors is an integer number (21030).

2⁸¹²⁸⁷ is an apocalyptic number.

81287 is a deficient number, since it is larger than the sum of its proper divisors (2833).

81287 is a wasteful number, since it uses less digits than its factorization.

81287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2832.

The product of its digits is 896, while the sum is 26.

The square root of 81287 is about 285.1087511810. The cubic root of 81287 is about 43.3185288020.

It can be divided in two parts, 8 and 1287, that multiplied together give a triangular number (10296 = T₁₄₃).

The spelling of 81287 in words is "eighty-one thousand, two hundred eighty-seven".