81863208 has 96 divisors (see below), whose sum is σ = 257774400. Its totient is φ = 22984704.

The previous prime is 81863161. The next prime is 81863209. The reversal of 81863208 is 80236818.

81863208 is a `hidden beast` number, since 8 + 18 + 632 + 0 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (81863209) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28360 + ... + 31112.

It is an arithmetic number, because the mean of its divisors is an integer number (2685150).

Almost surely, 2^81863208 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 81863208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128887200).

81863208 is an abundant number, since it is smaller than the sum of its proper divisors (175911192).

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

81863208 is a wasteful number, since it uses less digits than its factorization.

81863208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2831 (or 2824 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 81863208 is about 9047.8289108493. The cubic root of 81863208 is about 434.2064326898.

The spelling of 81863208 in words is "eighty-one million, eight hundred sixty-three thousand, two hundred eight".