81916043 has 16 divisors (see below), whose sum is σ = 92731392. Its totient is φ = 71688000.

The previous prime is 81916033. The next prime is 81916063. The reversal of 81916043 is 34061918.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81916043 - 2⁴ = 81916027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81916033) 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 in 15 ways as a sum of consecutive naturals, for example, 78938 + ... + 79968.

It is an arithmetic number, because the mean of its divisors is an integer number (5795712).

Almost surely, 2^81916043 is an apocalyptic number.

81916043 is a deficient number, since it is larger than the sum of its proper divisors (10815349).

81916043 is a wasteful number, since it uses less digits than its factorization.

81916043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1306.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 81916043 is about 9050.7482011158. The cubic root of 81916043 is about 434.2998257363.

The spelling of 81916043 in words is "eighty-one million, nine hundred sixteen thousand, forty-three".