81839912 has 32 divisors (see below), whose sum is σ = 191315520. Its totient is φ = 31885440.

The previous prime is 81839869. The next prime is 81839917. The reversal of 81839912 is 21993818.

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81839912.

It is not an unprimeable number, because it can be changed into a prime (81839917) 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 7 ways as a sum of consecutive naturals, for example, 65813 + ... + 67044.

It is an arithmetic number, because the mean of its divisors is an integer number (5978610).

Almost surely, 2^81839912 is an apocalyptic number.

It is an amenable number.

81839912 is an abundant number, since it is smaller than the sum of its proper divisors (109475608).

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

81839912 is a wasteful number, since it uses less digits than its factorization.

81839912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132881 (or 132877 counting only the distinct ones).

The product of its digits is 31104, while the sum is 41.

The square root of 81839912 is about 9046.5414385830. The cubic root of 81839912 is about 434.1652410770.

The spelling of 81839912 in words is "eighty-one million, eight hundred thirty-nine thousand, nine hundred twelve".