81359616 has 144 divisors (see below), whose sum is σ = 242091360. Its totient is φ = 24084480.

The previous prime is 81359599. The next prime is 81359627. The reversal of 81359616 is 61695318.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 289396 + ... + 289676.

It is an arithmetic number, because the mean of its divisors is an integer number (1681190).

Almost surely, 2^81359616 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 81359616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121045680).

81359616 is an abundant number, since it is smaller than the sum of its proper divisors (160731744).

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

81359616 is a wasteful number, since it uses less digits than its factorization.

81359616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342 (or 328 counting only the distinct ones).

The product of its digits is 38880, while the sum is 39.

The square root of 81359616 is about 9019.9565409153. The cubic root of 81359616 is about 433.3142418939.

The spelling of 81359616 in words is "eighty-one million, three hundred fifty-nine thousand, six hundred sixteen".