21717216873 has 24 divisors (see below), whose sum is σ = 35324979456. Its totient is φ = 12737368800.

The previous prime is 21717216793. The next prime is 21717216887. The reversal of 21717216873 is 37861271712.

It is not a de Polignac number, because 21717216873 - 2⁸ = 21717216617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21717216173) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3535090 + ... + 3541227.

It is an arithmetic number, because the mean of its divisors is an integer number (1471874144).

Almost surely, 2^21717216873 is an apocalyptic number.

It is an amenable number.

21717216873 is a deficient number, since it is larger than the sum of its proper divisors (13607762583).

21717216873 is a wasteful number, since it uses less digits than its factorization.

21717216873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7076365 (or 7076362 counting only the distinct ones).

The product of its digits is 197568, while the sum is 45.

The spelling of 21717216873 in words is "twenty-one billion, seven hundred seventeen million, two hundred sixteen thousand, eight hundred seventy-three".