81717384 has 64 divisors (see below), whose sum is σ = 234253440. Its totient is φ = 23270400.

The previous prime is 81717371. The next prime is 81717431. The reversal of 81717384 is 48371718.

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

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 66762 + ... + 67974.

It is an arithmetic number, because the mean of its divisors is an integer number (3660210).

Almost surely, 2^81717384 is an apocalyptic number.

81717384 is a gapful number since it is divisible by the number (84) 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 81717384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117126720).

81717384 is an abundant number, since it is smaller than the sum of its proper divisors (152536056).

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

81717384 is a wasteful number, since it uses less digits than its factorization.

81717384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1630 (or 1626 counting only the distinct ones).

The product of its digits is 37632, while the sum is 39.

The square root of 81717384 is about 9039.7668111517. The cubic root of 81717384 is about 433.9484602589.

The spelling of 81717384 in words is "eighty-one million, seven hundred seventeen thousand, three hundred eighty-four".