81218171667 has 8 divisors (see below), whose sum is σ = 108293688720. Its totient is φ = 54144051200.

The previous prime is 81218171659. The next prime is 81218171689. The reversal of 81218171667 is 76617181218.

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

It is a cyclic number.

It is not a de Polignac number, because 81218171667 - 2³ = 81218171659 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81218172667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 204942 + ... + 452147.

It is an arithmetic number, because the mean of its divisors is an integer number (13536711090).

Almost surely, 2^81218171667 is an apocalyptic number.

81218171667 is a deficient number, since it is larger than the sum of its proper divisors (27075517053).

81218171667 is a wasteful number, since it uses less digits than its factorization.

81218171667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 698293.

The product of its digits is 225792, while the sum is 48.

The spelling of 81218171667 in words is "eighty-one billion, two hundred eighteen million, one hundred seventy-one thousand, six hundred sixty-seven".