81544665327 has 4 divisors (see below), whose sum is σ = 108726220440. Its totient is φ = 54363110216.

The previous prime is 81544665311. The next prime is 81544665347. The reversal of 81544665327 is 72356644518.

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 81544665327 - 2⁴ = 81544665311 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81544665327.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81544665347) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13590777552 + ... + 13590777557.

It is an arithmetic number, because the mean of its divisors is an integer number (27181555110).

Almost surely, 2^81544665327 is an apocalyptic number.

81544665327 is a deficient number, since it is larger than the sum of its proper divisors (27181555113).

81544665327 is a wasteful number, since it uses less digits than its factorization.

81544665327 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27181555112.

The product of its digits is 4838400, while the sum is 51.

The spelling of 81544665327 in words is "eighty-one billion, five hundred forty-four million, six hundred sixty-five thousand, three hundred twenty-seven".