81823247 has 4 divisors (see below), whose sum is σ = 89261736. Its totient is φ = 74384760.

The previous prime is 81823241. The next prime is 81823267. The reversal of 81823247 is 74232818.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81823247 - 2⁸ = 81822991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81823241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3719228 + ... + 3719249.

It is an arithmetic number, because the mean of its divisors is an integer number (22315434).

Almost surely, 2^81823247 is an apocalyptic number.

81823247 is a deficient number, since it is larger than the sum of its proper divisors (7438489).

81823247 is a wasteful number, since it uses less digits than its factorization.

81823247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7438488.

The product of its digits is 21504, while the sum is 35.

The square root of 81823247 is about 9045.6203214594. The cubic root of 81823247 is about 434.1357694955.

It can be divided in two parts, 81 and 823247, that added together give a palindrome (823328).

The spelling of 81823247 in words is "eighty-one million, eight hundred twenty-three thousand, two hundred forty-seven".