81380 has 24 divisors (see below), whose sum is σ = 184632. Its totient is φ = 29952.

The previous prime is 81373. The next prime is 81401. The reversal of 81380 is 8318.

81380 is an esthetic number in base 5, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 4 ways, for example, as 4096 + 77284 = 64^2 + 278^2 .

It is a Smith number, since the sum of its digits (20) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (20).

81380 is an undulating number in base 5.

It is an unprimeable number.

81380 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 7 ways as a sum of consecutive naturals, for example, 104 + ... + 416.

It is an arithmetic number, because the mean of its divisors is an integer number (7693).

2⁸¹³⁸⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92316).

81380 is an abundant number, since it is smaller than the sum of its proper divisors (103252).

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

81380 is a wasteful number, since it uses less digits than its factorization.

81380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 333 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 81380 is about 285.2718002187. The cubic root of 81380 is about 43.3350426676.

Adding to 81380 its reverse (8318), we get a palindrome (89698).

The spelling of 81380 in words is "eighty-one thousand, three hundred eighty".