81912 has 16 divisors (see below), whose sum is σ = 204840. Its totient is φ = 27296.

The previous prime is 81901. The next prime is 81919. The reversal of 81912 is 21918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81919) by changing a digit.

81912 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1683 + ... + 1730.

2⁸¹⁹¹² is an apocalyptic number.

It is an amenable number.

81912 is an abundant number, since it is smaller than the sum of its proper divisors (122928).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102420).

81912 is a wasteful number, since it uses less digits than its factorization.

81912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3422 (or 3418 counting only the distinct ones).

The product of its digits is 144, while the sum is 21.

The square root of 81912 is about 286.2027253539. The cubic root of 81912 is about 43.4292680603.

The spelling of 81912 in words is "eighty-one thousand, nine hundred twelve".