81575666657518 has 8 divisors (see below), whose sum is σ = 133487454530520. Its totient is φ = 37079848480680.

The previous prime is 81575666657437. The next prime is 81575666657579.

81575666657518 is nontrivially palindromic in base 10.

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

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1853992424013 + ... + 1853992424056.

It is an arithmetic number, because the mean of its divisors is an integer number (16685931816315).

Almost surely, 2^{81575666657518} is an apocalyptic number.

81575666657518 is a deficient number, since it is larger than the sum of its proper divisors (51911787873002).

81575666657518 is a wasteful number, since it uses less digits than its factorization.

81575666657518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3707984848082.

The product of its digits is 2540160000, while the sum is 76.

The spelling of 81575666657518 in words is "eighty-one trillion, five hundred seventy-five billion, six hundred sixty-six million, six hundred fifty-seven thousand, five hundred eighteen".