16641665 has 8 divisors (see below), whose sum is σ = 20194920. Its totient is φ = 13163392.

The previous prime is 16641649. The next prime is 16641697. The reversal of 16641665 is 56614661.

It can be written as a sum of positive squares in 4 ways, for example, as 27889 + 16613776 = 167^2 + 4076^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 16641665 - 2⁴ = 16641649 is a prime.

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, 18254 + ... + 19143.

It is an arithmetic number, because the mean of its divisors is an integer number (2524365).

Almost surely, 2^16641665 is an apocalyptic number.

It is an amenable number.

16641665 is a deficient number, since it is larger than the sum of its proper divisors (3553255).

16641665 is an equidigital number, since it uses as much as digits as its factorization.

16641665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37491.

The product of its digits is 25920, while the sum is 35.

The square root of 16641665 is about 4079.4196891225. The cubic root of 16641665 is about 255.3086867903.

The spelling of 16641665 in words is "sixteen million, six hundred forty-one thousand, six hundred sixty-five".