81281847 has 16 divisors (see below), whose sum is σ = 111144960. Its totient is φ = 52813152.

The previous prime is 81281833. The next prime is 81281869. The reversal of 81281847 is 74818218.

It is a happy number.

It is not a de Polignac number, because 81281847 - 2⁸ = 81281591 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81288847) 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 15 ways as a sum of consecutive naturals, for example, 36858 + ... + 39000.

It is an arithmetic number, because the mean of its divisors is an integer number (6946560).

Almost surely, 2^81281847 is an apocalyptic number.

81281847 is a deficient number, since it is larger than the sum of its proper divisors (29863113).

81281847 is a wasteful number, since it uses less digits than its factorization.

81281847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2462.

The product of its digits is 28672, while the sum is 39.

The square root of 81281847 is about 9015.6445693029. The cubic root of 81281847 is about 433.1761342360.

It can be divided in two parts, 81281 and 847, that added together give a palindrome (82128).

The spelling of 81281847 in words is "eighty-one million, two hundred eighty-one thousand, eight hundred forty-seven".