81517600 has 144 divisors (see below), whose sum is σ = 217486080. Its totient is φ = 29721600.

The previous prime is 81517571. The next prime is 81517607. The reversal of 81517600 is 671518.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81517607) 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 23 ways as a sum of consecutive naturals, for example, 471114 + ... + 471286.

It is an arithmetic number, because the mean of its divisors is an integer number (1510320).

Almost surely, 2^81517600 is an apocalyptic number.

81517600 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81517600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108743040).

81517600 is an abundant number, since it is smaller than the sum of its proper divisors (135968480).

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

81517600 is a wasteful number, since it uses less digits than its factorization.

81517600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 28.

The square root of 81517600 is about 9028.7097638588. The cubic root of 81517600 is about 433.5945302342.

It can be divided in two parts, 8151 and 7600, that added together give a palindrome (15751).

The spelling of 81517600 in words is "eighty-one million, five hundred seventeen thousand, six hundred".