81312608 has 48 divisors (see below), whose sum is σ = 174890016. Its totient is φ = 36986880.

The previous prime is 81312599. The next prime is 81312619. The reversal of 81312608 is 80621318.

It is a super-2 number, since 2×81312608² = 13223480439523328, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28160 + ... + 30912.

It is an arithmetic number, because the mean of its divisors is an integer number (3643542).

Almost surely, 2^81312608 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 81312608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87445008).

81312608 is an abundant number, since it is smaller than the sum of its proper divisors (93577408).

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

81312608 is a wasteful number, since it uses less digits than its factorization.

81312608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2847 (or 2839 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 81312608 is about 9017.3503868930. The cubic root of 81312608 is about 433.2307723090.

The spelling of 81312608 in words is "eighty-one million, three hundred twelve thousand, six hundred eight".