81156367168 has 84 divisors (see below), whose sum is σ = 170203294848. Its totient is φ = 38354238720.

The previous prime is 81156367153. The next prime is 81156367181. The reversal of 81156367168 is 86176365118.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 3657355 + ... + 3679477.

Almost surely, 2^81156367168 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81156367168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85101647424).

81156367168 is an abundant number, since it is smaller than the sum of its proper divisors (89046927680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81156367168 is a wasteful number, since it uses less digits than its factorization.

81156367168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22252 (or 22199 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 52.

The spelling of 81156367168 in words is "eighty-one billion, one hundred fifty-six million, three hundred sixty-seven thousand, one hundred sixty-eight".