16844173721 has 6 divisors (see below), whose sum is σ = 17777369322. Its totient is φ = 15957637920.

The previous prime is 16844173651. The next prime is 16844173727. The reversal of 16844173721 is 12737144861.

It can be written as a sum of positive squares in only one way, i.e., 15873228121 + 970945600 = 125989^2 + 31160^2 .

It is a de Polignac number, because none of the positive numbers 2^k-16844173721 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16844173727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23329520 + ... + 23330241.

It is an arithmetic number, because the mean of its divisors is an integer number (2962894887).

Almost surely, 2^16844173721 is an apocalyptic number.

It is an amenable number.

16844173721 is a deficient number, since it is larger than the sum of its proper divisors (933195601).

16844173721 is an equidigital number, since it uses as much as digits as its factorization.

16844173721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46659799 (or 46659780 counting only the distinct ones).

The product of its digits is 225792, while the sum is 44.

The spelling of 16844173721 in words is "sixteen billion, eight hundred forty-four million, one hundred seventy-three thousand, seven hundred twenty-one".