16991171 has 2 divisors, whose sum is σ = 16991172. Its totient is φ = 16991170.

The previous prime is 16991167. The next prime is 16991173. The reversal of 16991171 is 17119961.

It is a strong prime.

It is an emirp because it is prime and its reverse (17119961) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16991171 - 2² = 16991167 is a prime.

Together with 16991173, 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 (16991173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8495585 + 8495586.

It is an arithmetic number, because the mean of its divisors is an integer number (8495586).

Almost surely, 2^16991171 is an apocalyptic number.

16991171 is a deficient number, since it is larger than the sum of its proper divisors (1).

16991171 is an equidigital number, since it uses as much as digits as its factorization.

16991171 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3402, while the sum is 35.

The square root of 16991171 is about 4122.0348130505. The cubic root of 16991171 is about 257.0836379357.

The spelling of 16991171 in words is "sixteen million, nine hundred ninety-one thousand, one hundred seventy-one".