16691606417 has 4 divisors (see below), whose sum is σ = 17673465636. Its totient is φ = 15709747200.

The previous prime is 16691606401. The next prime is 16691606423. The reversal of 16691606417 is 71460619661.

It is a happy number.

It is a Cunningham number, because it is equal to 129196²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12995088016 + 3696518401 = 113996^2 + 60799^2 .

It is a cyclic number.

It is not a de Polignac number, because 16691606417 - 2⁴ = 16691606401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16691606447) 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 3 ways as a sum of consecutive naturals, for example, 490929584 + ... + 490929617.

It is an arithmetic number, because the mean of its divisors is an integer number (4418366409).

Almost surely, 2^16691606417 is an apocalyptic number.

16691606417 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

16691606417 is a deficient number, since it is larger than the sum of its proper divisors (981859219).

16691606417 is an equidigital number, since it uses as much as digits as its factorization.

16691606417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 981859218.

The product of its (nonzero) digits is 326592, while the sum is 47.

The spelling of 16691606417 in words is "sixteen billion, six hundred ninety-one million, six hundred six thousand, four hundred seventeen".