81517056 has 80 divisors (see below), whose sum is σ = 220444224. Its totient is φ = 26763264.

The previous prime is 81517027. The next prime is 81517097. The reversal of 81517056 is 65071518.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111765 + ... + 112491.

Almost surely, 2^81517056 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 81517056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110222112).

81517056 is an abundant number, since it is smaller than the sum of its proper divisors (138927168).

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

81517056 is an equidigital number, since it uses as much as digits as its factorization.

81517056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 821 (or 805 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 33.

The square root of 81517056 is about 9028.6796376879. The cubic root of 81517056 is about 433.5935657147.

It can be divided in two parts, 815 and 17056, that added together give a palindrome (17871).

The spelling of 81517056 in words is "eighty-one million, five hundred seventeen thousand, fifty-six".