81959616 has 84 divisors (see below), whose sum is σ = 247319800. Its totient is φ = 25878528.

The previous prime is 81959611. The next prime is 81959617. The reversal of 81959616 is 61695918.

It is not an unprimeable number, because it can be changed into a prime (81959611) 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 11 ways as a sum of consecutive naturals, for example, 7200 + ... + 14688.

Almost surely, 2^81959616 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 81959616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123659900).

81959616 is an abundant number, since it is smaller than the sum of its proper divisors (165360184).

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

81959616 is a wasteful number, since it uses less digits than its factorization.

81959616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7526 (or 7513 counting only the distinct ones).

The product of its digits is 116640, while the sum is 45.

The square root of 81959616 is about 9053.1550301539. The cubic root of 81959616 is about 434.3768167272.

The spelling of 81959616 in words is "eighty-one million, nine hundred fifty-nine thousand, six hundred sixteen".