81008658 has 48 divisors (see below), whose sum is σ = 182520000. Its totient is φ = 25935840.

The previous prime is 81008623. The next prime is 81008659. The reversal of 81008658 is 85680018.

It is not an unprimeable number, because it can be changed into a prime (81008659) 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, 162093 + ... + 162591.

It is an arithmetic number, because the mean of its divisors is an integer number (3802500).

Almost surely, 2^81008658 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81008658, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91260000).

81008658 is an abundant number, since it is smaller than the sum of its proper divisors (101511342).

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

81008658 is a wasteful number, since it uses less digits than its factorization.

81008658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 847 (or 844 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The square root of 81008658 is about 9000.4809871473. The cubic root of 81008658 is about 432.6902865884.

The spelling of 81008658 in words is "eighty-one million, eight thousand, six hundred fifty-eight".