21668172181667 has 8 divisors (see below), whose sum is σ = 24187727087040. Its totient is φ = 19240237454760.

The previous prime is 21668172181657. The next prime is 21668172181703. The reversal of 21668172181667 is 76618127186612.

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 21668172181667 - 2⁴ = 21668172181651 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21668172181657) 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, 22905044117 + ... + 22905045062.

It is an arithmetic number, because the mean of its divisors is an integer number (3023465885880).

Almost surely, 2^{21668172181667} is an apocalyptic number.

21668172181667 is a deficient number, since it is larger than the sum of its proper divisors (2519554905373).

21668172181667 is a wasteful number, since it uses less digits than its factorization.

21668172181667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45810089233.

The product of its digits is 16257024, while the sum is 62.

The spelling of 21668172181667 in words is "twenty-one trillion, six hundred sixty-eight billion, one hundred seventy-two million, one hundred eighty-one thousand, six hundred sixty-seven".