81242 has 12 divisors (see below), whose sum is σ = 141930. Its totient is φ = 34776.

The previous prime is 81239. The next prime is 81281. The reversal of 81242 is 24218.

It can be written as a sum of positive squares in only one way, i.e., 67081 + 14161 = 259^2 + 119^2 .

It is a plaindrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 81242.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 317 + ... + 512.

2⁸¹²⁴² is an apocalyptic number.

81242 is a deficient number, since it is larger than the sum of its proper divisors (60688).

81242 is a wasteful number, since it uses less digits than its factorization.

81242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845 (or 838 counting only the distinct ones).

The product of its digits is 128, while the sum is 17.

The square root of 81242 is about 285.0298230010. The cubic root of 81242 is about 43.3105336998.

Subtracting from 81242 its sum of digits (17), we obtain a square (81225 = 285²).

It can be divided in two parts, 81 and 242, that added together give a palindrome (323).

The spelling of 81242 in words is "eighty-one thousand, two hundred forty-two".