81887 has 4 divisors (see below), whose sum is σ = 88200. Its totient is φ = 75576.

The previous prime is 81883. The next prime is 81899. The reversal of 81887 is 78818.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78818 = 2 ⋅39409.

It is a cyclic number.

It is not a de Polignac number, because 81887 - 2² = 81883 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81883) 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, 3137 + ... + 3162.

It is an arithmetic number, because the mean of its divisors is an integer number (22050).

2⁸¹⁸⁸⁷ is an apocalyptic number.

81887 is a deficient number, since it is larger than the sum of its proper divisors (6313).

81887 is a wasteful number, since it uses less digits than its factorization.

81887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6312.

The product of its digits is 3584, while the sum is 32.

The square root of 81887 is about 286.1590466856. The cubic root of 81887 is about 43.4248493257.

The spelling of 81887 in words is "eighty-one thousand, eight hundred eighty-seven".