81996588 has 36 divisors (see below), whose sum is σ = 212874480. Its totient is φ = 26593056.

The previous prime is 81996569. The next prime is 81996589. The reversal of 81996588 is 88569918.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81996589) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 29448 + ... + 32111.

It is an arithmetic number, because the mean of its divisors is an integer number (5913180).

Almost surely, 2^81996588 is an apocalyptic number.

It is an amenable number.

81996588 is an abundant number, since it is smaller than the sum of its proper divisors (130877892).

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

81996588 is a wasteful number, since it uses less digits than its factorization.

81996588 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61606 (or 61601 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 54.

The square root of 81996588 is about 9055.1967399941. The cubic root of 81996588 is about 434.4421227328.

The spelling of 81996588 in words is "eighty-one million, nine hundred ninety-six thousand, five hundred eighty-eight".