81717888 has 192 divisors, whose sum is σ = 260932320. Its totient is φ = 22579200.

The previous prime is 81717887. The next prime is 81717907. The reversal of 81717888 is 88871718.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (81717887) 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, 809038 + ... + 809138.

Almost surely, 2^81717888 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 81717888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130466160).

81717888 is an abundant number, since it is smaller than the sum of its proper divisors (179214432).

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

81717888 is a wasteful number, since it uses less digits than its factorization.

81717888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 156 counting only the distinct ones).

The product of its digits is 200704, while the sum is 48.

The square root of 81717888 is about 9039.7946879340. The cubic root of 81717888 is about 433.9493523970.

The spelling of 81717888 in words is "eighty-one million, seven hundred seventeen thousand, eight hundred eighty-eight".