81387 has 6 divisors (see below), whose sum is σ = 117572. Its totient is φ = 54252.

The previous prime is 81373. The next prime is 81401. The reversal of 81387 is 78318.

It is an interprime number because it is at equal distance from previous prime (81373) and next prime (81401).

It is not a de Polignac number, because 81387 - 2⁴ = 81371 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81387.

It is not an unprimeable number, because it can be changed into a prime (81307) 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, 4513 + ... + 4530.

2⁸¹³⁸⁷ is an apocalyptic number.

81387 is a deficient number, since it is larger than the sum of its proper divisors (36185).

81387 is a wasteful number, since it uses less digits than its factorization.

81387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9049 (or 9046 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 81387 is about 285.2840689558. The cubic root of 81387 is about 43.3362851375.

It can be divided in two parts, 813 and 87, that added together give a square (900 = 30²).

The spelling of 81387 in words is "eighty-one thousand, three hundred eighty-seven".