81319 has 4 divisors (see below), whose sum is σ = 92944. Its totient is φ = 69696.

The previous prime is 81307. The next prime is 81331. The reversal of 81319 is 91318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91318 = 2 ⋅45659.

It is an interprime number because it is at equal distance from previous prime (81307) and next prime (81331).

It is a cyclic number.

It is not a de Polignac number, because 81319 - 2¹³ = 73127 is a prime.

It is a super-2 number, since 2×81319² = 13225559522, which contains 22 as substring.

It is a Duffinian number.

81319 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 81319.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81349) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 5802 + ... + 5815.

It is an arithmetic number, because the mean of its divisors is an integer number (23236).

2⁸¹³¹⁹ is an apocalyptic number.

81319 is a deficient number, since it is larger than the sum of its proper divisors (11625).

81319 is a wasteful number, since it uses less digits than its factorization.

81319 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11624.

The product of its digits is 216, while the sum is 22.

The square root of 81319 is about 285.1648645959. The cubic root of 81319 is about 43.3242124130.

Subtracting 81319 from its reverse (91318), we obtain a palindrome (9999).

It can be divided in two parts, 81 and 319, that added together give a square (400 = 20²).

The spelling of 81319 in words is "eighty-one thousand, three hundred nineteen".