81739693 has 12 divisors (see below), whose sum is σ = 95304000. Its totient is φ = 69901272.

The previous prime is 81739663. The next prime is 81739699. The reversal of 81739693 is 39693718.

It is a de Polignac number, because none of the positive numbers 2^k-81739693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81739699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22780 + ... + 26122.

It is an arithmetic number, because the mean of its divisors is an integer number (7942000).

Almost surely, 2^81739693 is an apocalyptic number.

It is an amenable number.

81739693 is a deficient number, since it is larger than the sum of its proper divisors (13564307).

81739693 is a wasteful number, since it uses less digits than its factorization.

81739693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3856 (or 3849 counting only the distinct ones).

The product of its digits is 244944, while the sum is 46.

The square root of 81739693 is about 9041.0006636434. Note that the first 3 decimals coincide. The cubic root of 81739693 is about 433.9879462486.

The spelling of 81739693 in words is "eighty-one million, seven hundred thirty-nine thousand, six hundred ninety-three".