28666663 has 4 divisors (see below), whose sum is σ = 29276640. Its totient is φ = 28056688.

The previous prime is 28666643. The next prime is 28666721. The reversal of 28666663 is 36666682.

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-28666663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28666613) 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, 304918 + ... + 305011.

It is an arithmetic number, because the mean of its divisors is an integer number (7319160).

Almost surely, 2^28666663 is an apocalyptic number.

28666663 is a deficient number, since it is larger than the sum of its proper divisors (609977).

28666663 is an equidigital number, since it uses as much as digits as its factorization.

28666663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 609976.

The product of its digits is 373248, while the sum is 43.

The square root of 28666663 is about 5354.1257923213. The cubic root of 28666663 is about 306.0499975262.

The spelling of 28666663 in words is "twenty-eight million, six hundred sixty-six thousand, six hundred sixty-three".