81812384 has 48 divisors (see below), whose sum is σ = 166634496. Its totient is φ = 39513600.

The previous prime is 81812363. The next prime is 81812387. The reversal of 81812384 is 48321818.

It is not an unprimeable number, because it can be changed into a prime (81812387) 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, 166379 + ... + 166869.

It is an arithmetic number, because the mean of its divisors is an integer number (3471552).

Almost surely, 2^81812384 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81812384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83317248).

81812384 is an abundant number, since it is smaller than the sum of its proper divisors (84822112).

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

81812384 is a wasteful number, since it uses less digits than its factorization.

81812384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669 (or 661 counting only the distinct ones).

The product of its digits is 12288, while the sum is 35.

The square root of 81812384 is about 9045.0198451966. The cubic root of 81812384 is about 434.1165564325.

The spelling of 81812384 in words is "eighty-one million, eight hundred twelve thousand, three hundred eighty-four".