81609696 has 108 divisors (see below), whose sum is σ = 270014472. Its totient is φ = 23313024.

The previous prime is 81609659. The next prime is 81609709. The reversal of 81609696 is 69690618.

81609696 is a modest number, since divided by 9696 gives 8160 as remainder.

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 17 ways as a sum of consecutive naturals, for example, 11221 + ... + 17003.

It is an arithmetic number, because the mean of its divisors is an integer number (2500134).

Almost surely, 2^81609696 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 81609696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135007236).

81609696 is an abundant number, since it is smaller than the sum of its proper divisors (188404776).

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

81609696 is a wasteful number, since it uses less digits than its factorization.

81609696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5813 (or 5795 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 81609696 is about 9033.8084991879. The cubic root of 81609696 is about 433.7577558984.

The spelling of 81609696 in words is "eighty-one million, six hundred nine thousand, six hundred ninety-six".