81916 has 6 divisors (see below), whose sum is σ = 143360. Its totient is φ = 40956.

The previous prime is 81901. The next prime is 81919. The reversal of 81916 is 61918.

It is a congruent number.

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

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 as a sum of consecutive naturals, namely, 10236 + ... + 10243.

2⁸¹⁹¹⁶ is an apocalyptic number.

It is an amenable number.

81916 is a deficient number, since it is larger than the sum of its proper divisors (61444).

81916 is a wasteful number, since it uses less digits than its factorization.

81916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20483 (or 20481 counting only the distinct ones).

The product of its digits is 432, while the sum is 25.

The square root of 81916 is about 286.2097133222. The cubic root of 81916 is about 43.4299749744.

The spelling of 81916 in words is "eighty-one thousand, nine hundred sixteen".