81750 has 32 divisors (see below), whose sum is σ = 205920. Its totient is φ = 21600.

The previous prime is 81749. The next prime is 81761. The reversal of 81750 is 5718.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 696 + ... + 804.

It is an arithmetic number, because the mean of its divisors is an integer number (6435).

2⁸¹⁷⁵⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81750, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102960).

81750 is an abundant number, since it is smaller than the sum of its proper divisors (124170).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81750 is a wasteful number, since it uses less digits than its factorization.

81750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 21.

The square root of 81750 is about 285.9195691099. The cubic root of 81750 is about 43.4006186778.

The spelling of 81750 in words is "eighty-one thousand, seven hundred fifty".