81075781532159 has 4 divisors (see below), whose sum is σ = 83267018870904. Its totient is φ = 78884544193416.

The previous prime is 81075781532131. The next prime is 81075781532173. The reversal of 81075781532159 is 95123518757018.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81075781532159 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 (81075781532959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1095618669317 + ... + 1095618669390.

It is an arithmetic number, because the mean of its divisors is an integer number (20816754717726).

Almost surely, 2^{81075781532159} is an apocalyptic number.

81075781532159 is a deficient number, since it is larger than the sum of its proper divisors (2191237338745).

81075781532159 is a wasteful number, since it uses less digits than its factorization.

81075781532159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2191237338744.

The product of its (nonzero) digits is 21168000, while the sum is 62.

The spelling of 81075781532159 in words is "eighty-one trillion, seventy-five billion, seven hundred eighty-one million, five hundred thirty-two thousand, one hundred fifty-nine".