81689418992 has 10 divisors (see below), whose sum is σ = 158273249328. Its totient is φ = 40844709488.

The previous prime is 81689418991. The next prime is 81689419013. The reversal of 81689418992 is 29981498618.

It is a super-2 number, since 2×81689418992² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81689418991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2552794328 + ... + 2552794359.

Almost surely, 2^81689418992 is an apocalyptic number.

It is an amenable number.

81689418992 is a deficient number, since it is larger than the sum of its proper divisors (76583830336).

81689418992 is a wasteful number, since it uses less digits than its factorization.

81689418992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5105588695 (or 5105588689 counting only the distinct ones).

The product of its digits is 17915904, while the sum is 65.

The spelling of 81689418992 in words is "eighty-one billion, six hundred eighty-nine million, four hundred eighteen thousand, nine hundred ninety-two".