81547956791 has 8 divisors (see below), whose sum is σ = 93199987584. Its totient is φ = 69896506680.

The previous prime is 81547956779. The next prime is 81547956803. The reversal of 81547956791 is 19765974518.

It is an interprime number because it is at equal distance from previous prime (81547956779) and next prime (81547956803).

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

It is not a de Polignac number, because 81547956791 - 2¹⁸ = 81547694647 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 (81547956731) 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, 215516 + ... + 457758.

It is an arithmetic number, because the mean of its divisors is an integer number (11649998448).

Almost surely, 2^81547956791 is an apocalyptic number.

81547956791 is a deficient number, since it is larger than the sum of its proper divisors (11652030793).

81547956791 is a wasteful number, since it uses less digits than its factorization.

81547956791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290341.

The product of its digits is 19051200, while the sum is 62.

The spelling of 81547956791 in words is "eighty-one billion, five hundred forty-seven million, nine hundred fifty-six thousand, seven hundred ninety-one".