16662809 has 2 divisors, whose sum is σ = 16662810. Its totient is φ = 16662808.

The previous prime is 16662803. The next prime is 16662827. The reversal of 16662809 is 90826661.

16662809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10272025 + 6390784 = 3205^2 + 2528^2 .

It is a cyclic number.

It is not a de Polignac number, because 16662809 - 2⁸ = 16662553 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16662803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8331404 + 8331405.

It is an arithmetic number, because the mean of its divisors is an integer number (8331405).

Almost surely, 2^16662809 is an apocalyptic number.

It is an amenable number.

16662809 is a deficient number, since it is larger than the sum of its proper divisors (1).

16662809 is an equidigital number, since it uses as much as digits as its factorization.

16662809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 16662809 is about 4082.0104115497. The cubic root of 16662809 is about 255.4167681681.

It can be divided in two parts, 16662 and 809, that added together give a palindrome (17471).

The spelling of 16662809 in words is "sixteen million, six hundred sixty-two thousand, eight hundred nine".