81156000 has 96 divisors (see below), whose sum is σ = 265906368. Its totient is φ = 21638400.

The previous prime is 81155993. The next prime is 81156001. The reversal of 81156000 is 65118.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-3 number, since 3×81156000³ (a number of 25 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (81156001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8619 + ... + 15381.

It is an arithmetic number, because the mean of its divisors is an integer number (2769858).

Almost surely, 2^81156000 is an apocalyptic number.

81156000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81156000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132953184).

81156000 is an abundant number, since it is smaller than the sum of its proper divisors (184750368).

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

81156000 is a wasteful number, since it uses less digits than its factorization.

81156000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6791 (or 6773 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 81156000 is about 9008.6624978406. The cubic root of 81156000 is about 432.9524595474.

The spelling of 81156000 in words is "eighty-one million, one hundred fifty-six thousand".