21711816217 has 8 divisors (see below), whose sum is σ = 26722235456. Its totient is φ = 17178579792.

The previous prime is 21711816179. The next prime is 21711816221. The reversal of 21711816217 is 71261811712.

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 21711816217 - 2³¹ = 19564332569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21711816257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119295603 + ... + 119295784.

It is an arithmetic number, because the mean of its divisors is an integer number (3340279432).

Almost surely, 2^21711816217 is an apocalyptic number.

It is an amenable number.

21711816217 is a deficient number, since it is larger than the sum of its proper divisors (5010419239).

21711816217 is a wasteful number, since it uses less digits than its factorization.

21711816217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238591407.

The product of its digits is 9408, while the sum is 37.

The spelling of 21711816217 in words is "twenty-one billion, seven hundred eleven million, eight hundred sixteen thousand, two hundred seventeen".