81388223 has 16 divisors (see below), whose sum is σ = 95510016. Its totient is φ = 67915680.

The previous prime is 81388169. The next prime is 81388247. The reversal of 81388223 is 32288318.

It is a happy number.

It is not a de Polignac number, because 81388223 - 2²⁰ = 80339647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81387223) 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 15 ways as a sum of consecutive naturals, for example, 40265 + ... + 42237.

It is an arithmetic number, because the mean of its divisors is an integer number (5969376).

Almost surely, 2^81388223 is an apocalyptic number.

81388223 is a gapful number since it is divisible by the number (83) formed by its first and last digit.

81388223 is a deficient number, since it is larger than the sum of its proper divisors (14121793).

81388223 is a wasteful number, since it uses less digits than its factorization.

81388223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2134.

The product of its digits is 18432, while the sum is 35.

The square root of 81388223 is about 9021.5421630672. The cubic root of 81388223 is about 433.3650220745.

It can be divided in two parts, 8138 and 8223, that added together give a palindrome (16361).

The spelling of 81388223 in words is "eighty-one million, three hundred eighty-eight thousand, two hundred twenty-three".