81768128 has 56 divisors (see below), whose sum is σ = 182380128. Its totient is φ = 36089856.

The previous prime is 81768119. The next prime is 81768143. The reversal of 81768128 is 82186718.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17000 + ... + 21272.

It is an arithmetic number, because the mean of its divisors is an integer number (3256788).

Almost surely, 2^81768128 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 81768128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91190064).

81768128 is an abundant number, since it is smaller than the sum of its proper divisors (100612000).

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

81768128 is a wasteful number, since it uses less digits than its factorization.

81768128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4321 (or 4311 counting only the distinct ones).

The product of its digits is 43008, while the sum is 41.

The square root of 81768128 is about 9042.5730851346. The cubic root of 81768128 is about 434.0382645869.

The spelling of 81768128 in words is "eighty-one million, seven hundred sixty-eight thousand, one hundred twenty-eight".