81385903 has 8 divisors (see below), whose sum is σ = 83770848. Its totient is φ = 79010784.

The previous prime is 81385867. The next prime is 81385921. The reversal of 81385903 is 30958318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81385903 - 2⁹ = 81385391 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81385933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16425 + ... + 20797.

It is an arithmetic number, because the mean of its divisors is an integer number (10471356).

Almost surely, 2^81385903 is an apocalyptic number.

81385903 is a deficient number, since it is larger than the sum of its proper divisors (2384945).

81385903 is a wasteful number, since it uses less digits than its factorization.

81385903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4913.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 81385903 is about 9021.4135810304. The cubic root of 81385903 is about 433.3609042944.

It can be divided in two parts, 8138 and 5903, that added together give a palindrome (14041).

The spelling of 81385903 in words is "eighty-one million, three hundred eighty-five thousand, nine hundred three".