81038947 has 4 divisors (see below), whose sum is σ = 88406136. Its totient is φ = 73671760.

The previous prime is 81038939. The next prime is 81038953. The reversal of 81038947 is 74983018.

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 81038947 - 2³ = 81038939 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81038957) 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, 3683578 + ... + 3683599.

It is an arithmetic number, because the mean of its divisors is an integer number (22101534).

Almost surely, 2^81038947 is an apocalyptic number.

81038947 is a deficient number, since it is larger than the sum of its proper divisors (7367189).

81038947 is a wasteful number, since it uses less digits than its factorization.

81038947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7367188.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 81038947 is about 9002.1634621906. The cubic root of 81038947 is about 432.7442072571.

The spelling of 81038947 in words is "eighty-one million, thirty-eight thousand, nine hundred forty-seven".