16657609 has 2 divisors, whose sum is σ = 16657610. Its totient is φ = 16657608.

The previous prime is 16657601. The next prime is 16657639. The reversal of 16657609 is 90675661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16605625 + 51984 = 4075^2 + 228^2 .

It is a cyclic number.

It is not a de Polignac number, because 16657609 - 2³ = 16657601 is a prime.

It is not a weakly prime, because it can be changed into another prime (16657601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8328804 + 8328805.

It is an arithmetic number, because the mean of its divisors is an integer number (8328805).

Almost surely, 2^16657609 is an apocalyptic number.

It is an amenable number.

16657609 is a deficient number, since it is larger than the sum of its proper divisors (1).

16657609 is an equidigital number, since it uses as much as digits as its factorization.

16657609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 68040, while the sum is 40.

The square root of 16657609 is about 4081.3734207984. The cubic root of 16657609 is about 255.3901959101.

It can be divided in two parts, 166 and 57609, that added together give a palindrome (57775).

The spelling of 16657609 in words is "sixteen million, six hundred fifty-seven thousand, six hundred nine".