81686068619 has 16 divisors (see below), whose sum is σ = 83987121504. Its totient is φ = 79419916800.

The previous prime is 81686068589. The next prime is 81686068627. The reversal of 81686068619 is 91686068618.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81686068619 is a prime.

It is a super-2 number, since 2×81686068619² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81686568619) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2555204 + ... + 2586974.

It is an arithmetic number, because the mean of its divisors is an integer number (5249195094).

Almost surely, 2^81686068619 is an apocalyptic number.

81686068619 is a deficient number, since it is larger than the sum of its proper divisors (2301052885).

81686068619 is a wasteful number, since it uses less digits than its factorization.

81686068619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32318.

The product of its (nonzero) digits is 5971968, while the sum is 59.

Subtracting 81686068619 from its reverse (91686068618), we obtain a palindrome (9999999999).

The spelling of 81686068619 in words is "eighty-one billion, six hundred eighty-six million, sixty-eight thousand, six hundred nineteen".