81047447 has 16 divisors (see below), whose sum is σ = 90679008. Its totient is φ = 71953920.

The previous prime is 81047437. The next prime is 81047459. The reversal of 81047447 is 74474018.

It is a cyclic number.

It is not a de Polignac number, because 81047447 - 2⁸ = 81047191 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 (81047437) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37868 + ... + 39950.

It is an arithmetic number, because the mean of its divisors is an integer number (5667438).

Almost surely, 2^81047447 is an apocalyptic number.

81047447 is a deficient number, since it is larger than the sum of its proper divisors (9631561).

81047447 is a wasteful number, since it uses less digits than its factorization.

81047447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2210.

The product of its (nonzero) digits is 25088, while the sum is 35.

The square root of 81047447 is about 9002.6355585462. The cubic root of 81047447 is about 432.7593365963.

It can be divided in two parts, 8104 and 7447, that added together give a palindrome (15551).

The spelling of 81047447 in words is "eighty-one million, forty-seven thousand, four hundred forty-seven".