81742257717 has 16 divisors (see below), whose sum is σ = 116861610240. Its totient is φ = 50640026112.

The previous prime is 81742257703. The next prime is 81742257719. The reversal of 81742257717 is 71775224718.

It is not a de Polignac number, because 81742257717 - 2⁸ = 81742257461 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 81742257717.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81742257719) 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 15 ways as a sum of consecutive naturals, for example, 10140208 + ... + 10148265.

It is an arithmetic number, because the mean of its divisors is an integer number (7303850640).

Almost surely, 2^81742257717 is an apocalyptic number.

It is an amenable number.

81742257717 is a deficient number, since it is larger than the sum of its proper divisors (35119352523).

81742257717 is a wasteful number, since it uses less digits than its factorization.

81742257717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20288572.

The product of its digits is 1536640, while the sum is 51.

The spelling of 81742257717 in words is "eighty-one billion, seven hundred forty-two million, two hundred fifty-seven thousand, seven hundred seventeen".