16917163721 has 2 divisors, whose sum is σ = 16917163722. Its totient is φ = 16917163720.

The previous prime is 16917163693. The next prime is 16917163723. The reversal of 16917163721 is 12736171961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10452199696 + 6464964025 = 102236^2 + 80405^2 .

It is a cyclic number.

It is not a de Polignac number, because 16917163721 - 2²⁶ = 16850054857 is a prime.

Together with 16917163723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16917163723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8458581860 + 8458581861.

It is an arithmetic number, because the mean of its divisors is an integer number (8458581861).

Almost surely, 2^16917163721 is an apocalyptic number.

It is an amenable number.

16917163721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16917163721 is an equidigital number, since it uses as much as digits as its factorization.

16917163721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 95256, while the sum is 44.

The spelling of 16917163721 in words is "sixteen billion, nine hundred seventeen million, one hundred sixty-three thousand, seven hundred twenty-one".