81493 has 4 divisors (see below), whose sum is σ = 82080. Its totient is φ = 80908.

The previous prime is 81463. The next prime is 81509. The reversal of 81493 is 39418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 39418 = 2 ⋅19709.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81493 is a prime.

It is a super-2 number, since 2×81493² = 13282218098, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81463) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48 + ... + 406.

It is an arithmetic number, because the mean of its divisors is an integer number (20520).

2⁸¹⁴⁹³ is an apocalyptic number.

It is an amenable number.

81493 is a deficient number, since it is larger than the sum of its proper divisors (587).

81493 is a wasteful number, since it uses less digits than its factorization.

81493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 586.

The product of its digits is 864, while the sum is 25.

The square root of 81493 is about 285.4697882439. The cubic root of 81493 is about 43.3550909803.

Adding to 81493 its sum of digits (25), we get a palindrome (81518).

The spelling of 81493 in words is "eighty-one thousand, four hundred ninety-three".