81716823 has 8 divisors (see below), whose sum is σ = 121062000. Its totient is φ = 54477864.

The previous prime is 81716749. The next prime is 81716827. The reversal of 81716823 is 32861718.

It is a de Polignac number, because none of the positive numbers 2^k-81716823 is a prime.

It is a super-2 number, since 2×81716823² = 13355278322426658, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81716827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1513248 + ... + 1513301.

It is an arithmetic number, because the mean of its divisors is an integer number (15132750).

Almost surely, 2^81716823 is an apocalyptic number.

81716823 is a deficient number, since it is larger than the sum of its proper divisors (39345177).

81716823 is a wasteful number, since it uses less digits than its factorization.

81716823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3026558 (or 3026552 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 81716823 is about 9039.7357815370. The cubic root of 81716823 is about 433.9474672199.

The spelling of 81716823 in words is "eighty-one million, seven hundred sixteen thousand, eight hundred twenty-three".