16660001 has 4 divisors (see below), whose sum is σ = 16673604. Its totient is φ = 16646400.

The previous prime is 16659997. The next prime is 16660013. The reversal of 16660001 is 10006661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10006661 = 7 ⋅1429523.

It can be written as a sum of positive squares in 2 ways, for example, as 3519376 + 13140625 = 1876^2 + 3625^2 .

It is a cyclic number.

It is not a de Polignac number, because 16660001 - 2² = 16659997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16660031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4760 + ... + 7481.

It is an arithmetic number, because the mean of its divisors is an integer number (4168401).

Almost surely, 2^16660001 is an apocalyptic number.

It is an amenable number.

16660001 is a deficient number, since it is larger than the sum of its proper divisors (13603).

16660001 is a wasteful number, since it uses less digits than its factorization.

16660001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13602.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 16660001 is about 4081.6664488907. Note that the first 3 decimals coincide. The cubic root of 16660001 is about 255.4024198355.

Adding to 16660001 its reverse (10006661), we get a palindrome (26666662).

The spelling of 16660001 in words is "sixteen million, six hundred sixty thousand, one".