81306 has 12 divisors (see below), whose sum is σ = 176202. Its totient is φ = 27096.

The previous prime is 81299. The next prime is 81307. The reversal of 81306 is 60318.

81306 is nontrivially palindromic in base 8.

It can be written as a sum of positive squares in only one way, i.e., 81225 + 81 = 285^2 + 9^2 .

It is a super-2 number, since 2×81306² = 13221331272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 4517 = 81306 / (8 + 1 + 3 + 0 + 6).

It is not an unprimeable number, because it can be changed into a prime (81307) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2241 + ... + 2276.

2⁸¹³⁰⁶ is an apocalyptic number.

81306 is an abundant number, since it is smaller than the sum of its proper divisors (94896).

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

81306 is a wasteful number, since it uses less digits than its factorization.

81306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4525 (or 4522 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 81306 is about 285.1420698529. The cubic root of 81306 is about 43.3219036259.

The spelling of 81306 in words is "eighty-one thousand, three hundred six".