It is a sphenic number, since it is the product of 3 distinct primes.
It is an unprimeable number.
Almost surely, 281755218 is an apocalyptic number.
81755218 is a wasteful number, since it uses less digits than its factorization.
81755218 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 163112.
The square root of 81755218 is about 9041.8592114675. The cubic root of 81755218 is about 434.0154206049.
Subtracting from 81755218 its reverse (81255718), we obtain a triangular number (499500 = T999).
The spelling of 81755218 in words is "eighty-one million, seven hundred fifty-five thousand, two hundred eighteen".