16691665 has 8 divisors (see below), whose sum is σ = 20225088. Its totient is φ = 13223280.

The previous prime is 16691659. The next prime is 16691687. The reversal of 16691665 is 56619661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16691665 - 2³ = 16691657 is a prime.

It is a super-2 number, since 2×16691665² = 557223360944450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15691 + ... + 16720.

It is an arithmetic number, because the mean of its divisors is an integer number (2528136).

Almost surely, 2^16691665 is an apocalyptic number.

It is an amenable number.

16691665 is a deficient number, since it is larger than the sum of its proper divisors (3533423).

16691665 is a wasteful number, since it uses less digits than its factorization.

16691665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32519.

The product of its digits is 58320, while the sum is 40.

The square root of 16691665 is about 4085.5434155079. The cubic root of 16691665 is about 255.5641233912.

The spelling of 16691665 in words is "sixteen million, six hundred ninety-one thousand, six hundred sixty-five".