81366208 has 168 divisors, whose sum is σ = 216204800. Its totient is φ = 29652480.

The previous prime is 81366193. The next prime is 81366217. The reversal of 81366208 is 80266318.

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 23 ways as a sum of consecutive naturals, for example, 1029913 + ... + 1029991.

Almost surely, 2^81366208 is an apocalyptic number.

81366208 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 81366208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108102400).

81366208 is an abundant number, since it is smaller than the sum of its proper divisors (134838592).

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

81366208 is a wasteful number, since it uses less digits than its factorization.

81366208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139 (or 118 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 81366208 is about 9020.3219454740. The cubic root of 81366208 is about 433.3259443842.

The spelling of 81366208 in words is "eighty-one million, three hundred sixty-six thousand, two hundred eight".