81385548 has 12 divisors (see below), whose sum is σ = 189899640. Its totient is φ = 27128512.

The previous prime is 81385543. The next prime is 81385559. The reversal of 81385548 is 84558318.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81385543) 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 3 ways as a sum of consecutive naturals, for example, 3391053 + ... + 3391076.

It is an arithmetic number, because the mean of its divisors is an integer number (15824970).

Almost surely, 2^81385548 is an apocalyptic number.

It is an amenable number.

81385548 is an abundant number, since it is smaller than the sum of its proper divisors (108514092).

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

81385548 is a wasteful number, since it uses less digits than its factorization.

81385548 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6782136 (or 6782134 counting only the distinct ones).

The product of its digits is 153600, while the sum is 42.

The square root of 81385548 is about 9021.3939056002. The cubic root of 81385548 is about 433.3602741962.

The spelling of 81385548 in words is "eighty-one million, three hundred eighty-five thousand, five hundred forty-eight".