81244481 has 4 divisors (see below), whose sum is σ = 81294000. Its totient is φ = 81194964.

The previous prime is 81244463. The next prime is 81244483. The reversal of 81244481 is 18444218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81244481 - 2¹⁸ = 80982337 is a prime.

It is a super-2 number, since 2×81244481² = 13201331385918722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81244483) 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, 22211 + ... + 25608.

It is an arithmetic number, because the mean of its divisors is an integer number (20323500).

Almost surely, 2^81244481 is an apocalyptic number.

It is an amenable number.

81244481 is a deficient number, since it is larger than the sum of its proper divisors (49519).

81244481 is a wasteful number, since it uses less digits than its factorization.

81244481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49518.

The product of its digits is 8192, while the sum is 32.

The square root of 81244481 is about 9013.5720444228. The cubic root of 81244481 is about 433.1097457333.

Adding to 81244481 its reverse (18444218), we get a palindrome (99688699).

The spelling of 81244481 in words is "eighty-one million, two hundred forty-four thousand, four hundred eighty-one".