16991917 has 16 divisors (see below), whose sum is σ = 18692352. Its totient is φ = 15396480.

The previous prime is 16991893. The next prime is 16991927. The reversal of 16991917 is 71919961.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16991917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16991927) 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 15 ways as a sum of consecutive naturals, for example, 34648 + ... + 35134.

It is an arithmetic number, because the mean of its divisors is an integer number (1168272).

Almost surely, 2^16991917 is an apocalyptic number.

It is an amenable number.

16991917 is a deficient number, since it is larger than the sum of its proper divisors (1700435).

16991917 is a wasteful number, since it uses less digits than its factorization.

16991917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 588.

The product of its digits is 30618, while the sum is 43.

The square root of 16991917 is about 4122.1253013464. The cubic root of 16991917 is about 257.0874003129.

The spelling of 16991917 in words is "sixteen million, nine hundred ninety-one thousand, nine hundred seventeen".