16656643 has 4 divisors (see below), whose sum is σ = 17231040. Its totient is φ = 16082248.

The previous prime is 16656631. The next prime is 16656649. The reversal of 16656643 is 34665661.

16656643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16656643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16656649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 287155 + ... + 287212.

It is an arithmetic number, because the mean of its divisors is an integer number (4307760).

Almost surely, 2^16656643 is an apocalyptic number.

16656643 is a deficient number, since it is larger than the sum of its proper divisors (574397).

16656643 is an equidigital number, since it uses as much as digits as its factorization.

16656643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574396.

The product of its digits is 77760, while the sum is 37.

The square root of 16656643 is about 4081.2550765665. The cubic root of 16656643 is about 255.3852589931.

The spelling of 16656643 in words is "sixteen million, six hundred fifty-six thousand, six hundred forty-three".