81450 has 36 divisors (see below), whose sum is σ = 220038. Its totient is φ = 21600.

The previous prime is 81439. The next prime is 81457. The reversal of 81450 is 5418.

It can be written as a sum of positive squares in 3 ways, for example, as 33489 + 47961 = 183^2 + 219^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81457) by changing a digit.

81450 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 360 + ... + 540.

2⁸¹⁴⁵⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110019).

81450 is an abundant number, since it is smaller than the sum of its proper divisors (138588).

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

81450 is a wasteful number, since it uses less digits than its factorization.

81450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 81450 is about 285.3944638566. The cubic root of 81450 is about 43.3474641620.

Adding to 81450 its reverse (5418), we get a palindrome (86868).

The spelling of 81450 in words is "eighty-one thousand, four hundred fifty".