21717216871 has 8 divisors (see below), whose sum is σ = 24822040064. Its totient is φ = 18612984600.

The previous prime is 21717216793. The next prime is 21717216887. The reversal of 21717216871 is 17861271712.

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

It is not a de Polignac number, because 21717216871 - 2¹¹ = 21717214823 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 (21717216071) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 65955 + ... + 218596.

It is an arithmetic number, because the mean of its divisors is an integer number (3102755008).

Almost surely, 2^21717216871 is an apocalyptic number.

21717216871 is a deficient number, since it is larger than the sum of its proper divisors (3104823193).

21717216871 is a wasteful number, since it uses less digits than its factorization.

21717216871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295461.

The product of its digits is 65856, while the sum is 43.

The spelling of 21717216871 in words is "twenty-one billion, seven hundred seventeen million, two hundred sixteen thousand, eight hundred seventy-one".