81385612 has 48 divisors (see below), whose sum is σ = 178940160. Its totient is φ = 31464000.

The previous prime is 81385589. The next prime is 81385631. The reversal of 81385612 is 21658318.

It is a super-2 number, since 2×81385612² = 13247235681229088, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41862 + ... + 43762.

It is an arithmetic number, because the mean of its divisors is an integer number (3727920).

Almost surely, 2^81385612 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 81385612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89470080).

81385612 is an abundant number, since it is smaller than the sum of its proper divisors (97554548).

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

81385612 is a wasteful number, since it uses less digits than its factorization.

81385612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2062 (or 2060 counting only the distinct ones).

The product of its digits is 11520, while the sum is 34.

The square root of 81385612 is about 9021.3974527232. The cubic root of 81385612 is about 433.3603877915.

The spelling of 81385612 in words is "eighty-one million, three hundred eighty-five thousand, six hundred twelve".