81968216 has 32 divisors (see below), whose sum is σ = 173076480. Its totient is φ = 36055200.

The previous prime is 81968189. The next prime is 81968231. The reversal of 81968216 is 61286918.

It is a congruent 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 7 ways as a sum of consecutive naturals, for example, 12296 + ... + 17751.

It is an arithmetic number, because the mean of its divisors is an integer number (5408640).

Almost surely, 2^81968216 is an apocalyptic number.

It is an amenable number.

81968216 is an abundant number, since it is smaller than the sum of its proper divisors (91108264).

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

81968216 is a wasteful number, since it uses less digits than its factorization.

81968216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30095 (or 30091 counting only the distinct ones).

The product of its digits is 41472, while the sum is 41.

The square root of 81968216 is about 9053.6299902304. The cubic root of 81968216 is about 434.3920092092.

The spelling of 81968216 in words is "eighty-one million, nine hundred sixty-eight thousand, two hundred sixteen".