81143568 has 90 divisors (see below), whose sum is σ = 249664142. Its totient is φ = 24583680.

The previous prime is 81143459. The next prime is 81143611. The reversal of 81143568 is 86534118.

81143568 is a `hidden beast` number, since 81 + 14 + 3 + 568 = 666.

It can be written as a sum of positive squares in only one way, i.e., 54641664 + 26501904 = 7392^2 + 5148^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 15096 + ... + 19752.

Almost surely, 2^81143568 is an apocalyptic number.

81143568 is a gapful number since it is divisible by the number (88) 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 81143568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124832071).

81143568 is an abundant number, since it is smaller than the sum of its proper divisors (168520574).

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

81143568 is a wasteful number, since it uses less digits than its factorization.

81143568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4693 (or 4673 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 81143568 is about 9007.9724688744. The cubic root of 81143568 is about 432.9303509342.

The spelling of 81143568 in words is "eighty-one million, one hundred forty-three thousand, five hundred sixty-eight".