81965850 has 48 divisors (see below), whose sum is σ = 204466080. Its totient is φ = 21729600.

The previous prime is 81965833. The next prime is 81965881. The reversal of 81965850 is 5856918.

It is a Curzon number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 25641 + ... + 28659.

It is an arithmetic number, because the mean of its divisors is an integer number (4259710).

Almost surely, 2^81965850 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81965850, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102233040).

81965850 is an abundant number, since it is smaller than the sum of its proper divisors (122500230).

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

81965850 is a wasteful number, since it uses less digits than its factorization.

81965850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3215 (or 3210 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 42.

The square root of 81965850 is about 9053.4993234660. The cubic root of 81965850 is about 434.3878296161.

The spelling of 81965850 in words is "eighty-one million, nine hundred sixty-five thousand, eight hundred fifty".