81244847 has 4 divisors (see below), whose sum is σ = 81264120. Its totient is φ = 81225576.

The previous prime is 81244781. The next prime is 81244861. The reversal of 81244847 is 74844218.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74844218 = 2 ⋅37422109.

It is a cyclic number.

It is not a de Polignac number, because 81244847 - 2⁸ = 81244591 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81244847.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81244897) 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 3 ways as a sum of consecutive naturals, for example, 293 + ... + 12750.

It is an arithmetic number, because the mean of its divisors is an integer number (20316030).

Almost surely, 2^81244847 is an apocalyptic number.

81244847 is a deficient number, since it is larger than the sum of its proper divisors (19273).

81244847 is a wasteful number, since it uses less digits than its factorization.

81244847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19272.

The product of its digits is 57344, while the sum is 38.

The square root of 81244847 is about 9013.5923471167. The cubic root of 81244847 is about 433.1103961074.

The spelling of 81244847 in words is "eighty-one million, two hundred forty-four thousand, eight hundred forty-seven".