81808768 has 32 divisors (see below), whose sum is σ = 168606000. Its totient is φ = 39492096.

The previous prime is 81808763. The next prime is 81808787. The reversal of 81808768 is 86780818.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81808763) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7308 + ... + 14731.

Almost surely, 2^81808768 is an apocalyptic number.

It is an amenable number.

81808768 is an abundant number, since it is smaller than the sum of its proper divisors (86797232).

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

81808768 is a wasteful number, since it uses less digits than its factorization.

81808768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22082 (or 22070 counting only the distinct ones).

The product of its (nonzero) digits is 172032, while the sum is 46.

The square root of 81808768 is about 9044.8199539847. The cubic root of 81808768 is about 434.1101605443.

The spelling of 81808768 in words is "eighty-one million, eight hundred eight thousand, seven hundred sixty-eight".