81865242 has 28 divisors (see below), whose sum is σ = 184115850. Its totient is φ = 27287928.

The previous prime is 81865229. The next prime is 81865261. The reversal of 81865242 is 24256818.

It can be written as a sum of positive squares in only one way, i.e., 60047001 + 21818241 = 7749^2 + 4671^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81865197 and 81865206.

It is an unprimeable number.

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 13 ways as a sum of consecutive naturals, for example, 26617 + ... + 29532.

Almost surely, 2^81865242 is an apocalyptic number.

81865242 is an abundant number, since it is smaller than the sum of its proper divisors (102250608).

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

81865242 is an equidigital number, since it uses as much as digits as its factorization.

81865242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56169 (or 56154 counting only the distinct ones).

The product of its digits is 30720, while the sum is 36.

The square root of 81865242 is about 9047.9413128070. The cubic root of 81865242 is about 434.2100288050.

The spelling of 81865242 in words is "eighty-one million, eight hundred sixty-five thousand, two hundred forty-two".