81390 has 16 divisors (see below), whose sum is σ = 195408. Its totient is φ = 21696.

The previous prime is 81373. The next prime is 81401. The reversal of 81390 is 9318.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1327 + ... + 1386.

It is an arithmetic number, because the mean of its divisors is an integer number (12213).

2⁸¹³⁹⁰ is an apocalyptic number.

81390 is an abundant number, since it is smaller than the sum of its proper divisors (114018).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97704).

81390 is a wasteful number, since it uses less digits than its factorization.

81390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2723.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 81390 is about 285.2893268245. The cubic root of 81390 is about 43.3368176028.

It can be divided in two parts, 813 and 90, that added together give a triangular number (903 = T₄₂).

The spelling of 81390 in words is "eighty-one thousand, three hundred ninety".