81601608 has 128 divisors (see below), whose sum is σ = 236390400. Its totient is φ = 23232000.

The previous prime is 81601601. The next prime is 81601627. The reversal of 81601608 is 80610618.

It is not an unprimeable number, because it can be changed into a prime (81601601) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 540333 + ... + 540483.

It is an arithmetic number, because the mean of its divisors is an integer number (1846800).

Almost surely, 2^81601608 is an apocalyptic number.

81601608 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81601608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118195200).

81601608 is an abundant number, since it is smaller than the sum of its proper divisors (154788792).

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

81601608 is a wasteful number, since it uses less digits than its factorization.

81601608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283 (or 279 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 81601608 is about 9033.3608363665. The cubic root of 81601608 is about 433.7434261116.

The spelling of 81601608 in words is "eighty-one million, six hundred one thousand, six hundred eight".