81375 has 32 divisors (see below), whose sum is σ = 159744. Its totient is φ = 36000.

The previous prime is 81373. The next prime is 81401. The reversal of 81375 is 57318.

81375 = 1² + 2² + ... + 62².

It is not a de Polignac number, because 81375 - 2¹ = 81373 is a prime.

Its product of digits (840) is a multiple of the sum of its prime factors (56).

It is a plaindrome in base 9 and base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2610 + ... + 2640.

It is an arithmetic number, because the mean of its divisors is an integer number (4992).

2⁸¹³⁷⁵ is an apocalyptic number.

81375 is a deficient number, since it is larger than the sum of its proper divisors (78369).

81375 is a wasteful number, since it uses less digits than its factorization.

81375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56 (or 46 counting only the distinct ones).

The product of its digits is 840, while the sum is 24.

The square root of 81375 is about 285.2630365119. The cubic root of 81375 is about 43.3341551455.

Adding to 81375 its product of digits (840), we get a triangular number (82215 = T₄₀₅).

It can be divided in two parts, 813 and 75, that added together give a palindrome (888).

The spelling of 81375 in words is "eighty-one thousand, three hundred seventy-five".