81808908 has 24 divisors (see below), whose sum is σ = 200934720. Its totient is φ = 25834320.

The previous prime is 81808901. The next prime is 81808921. The reversal of 81808908 is 80980818.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81808908.

It is not an unprimeable number, because it can be changed into a prime (81808901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 179178 + ... + 179633.

It is an arithmetic number, because the mean of its divisors is an integer number (8372280).

Almost surely, 2^81808908 is an apocalyptic number.

It is an amenable number.

81808908 is an abundant number, since it is smaller than the sum of its proper divisors (119125812).

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

81808908 is a wasteful number, since it uses less digits than its factorization.

81808908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 358837 (or 358835 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 42.

The square root of 81808908 is about 9044.8276932178. The cubic root of 81808908 is about 434.1104081762.

The spelling of 81808908 in words is "eighty-one million, eight hundred eight thousand, nine hundred eight".