81336768 has 56 divisors (see below), whose sum is σ = 219291408. Its totient is φ = 26597376.

The previous prime is 81336733. The next prime is 81336803. The reversal of 81336768 is 86763318.

It is an interprime number because it is at equal distance from previous prime (81336733) and next prime (81336803).

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 6180 + ... + 14172.

It is an arithmetic number, because the mean of its divisors is an integer number (3915918).

Almost surely, 2^81336768 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 81336768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109645704).

81336768 is an abundant number, since it is smaller than the sum of its proper divisors (137954640).

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

81336768 is a wasteful number, since it uses less digits than its factorization.

81336768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8061 (or 8051 counting only the distinct ones).

The product of its digits is 145152, while the sum is 42.

The square root of 81336768 is about 9018.6899270349. The cubic root of 81336768 is about 433.2736759425.

The spelling of 81336768 in words is "eighty-one million, three hundred thirty-six thousand, seven hundred sixty-eight".