81942817 has 8 divisors (see below), whose sum is σ = 89494272. Its totient is φ = 74408400.

The previous prime is 81942811. The next prime is 81942857. The reversal of 81942817 is 71824918.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81942817 - 2¹¹ = 81940769 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81942817.

It is not an unprimeable number, because it can be changed into a prime (81942811) 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, 7143 + ... + 14659.

It is an arithmetic number, because the mean of its divisors is an integer number (11186784).

Almost surely, 2^81942817 is an apocalyptic number.

It is an amenable number.

81942817 is a deficient number, since it is larger than the sum of its proper divisors (7551455).

81942817 is a wasteful number, since it uses less digits than its factorization.

81942817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8519.

The product of its digits is 32256, while the sum is 40.

The square root of 81942817 is about 9052.2271845110. The cubic root of 81942817 is about 434.3471370910.

It can be divided in two parts, 8194 and 2817, that added together give a palindrome (11011).

The spelling of 81942817 in words is "eighty-one million, nine hundred forty-two thousand, eight hundred seventeen".