81018505047 has 8 divisors (see below), whose sum is σ = 108061266544. Its totient is φ = 53994040128.

The previous prime is 81018505027. The next prime is 81018505049. The reversal of 81018505047 is 74050581018.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81018505047 - 2¹⁶ = 81018439511 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81018504996 and 81018505014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81018505049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4563808 + ... + 4581525.

It is an arithmetic number, because the mean of its divisors is an integer number (13507658318).

Almost surely, 2^81018505047 is an apocalyptic number.

81018505047 is a deficient number, since it is larger than the sum of its proper divisors (27042761497).

81018505047 is a wasteful number, since it uses less digits than its factorization.

81018505047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9148289.

The product of its (nonzero) digits is 44800, while the sum is 39.

The spelling of 81018505047 in words is "eighty-one billion, eighteen million, five hundred five thousand, forty-seven".