28666646 has 4 divisors (see below), whose sum is σ = 42999972. Its totient is φ = 14333322.

The previous prime is 28666643. The next prime is 28666721. The reversal of 28666646 is 64666682.

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

It is a junction number, because it is equal to n+sod(n) for n = 28666597 and 28666606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28666643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7166660 + ... + 7166663.

It is an arithmetic number, because the mean of its divisors is an integer number (10749993).

Almost surely, 2^28666646 is an apocalyptic number.

28666646 is a deficient number, since it is larger than the sum of its proper divisors (14333326).

28666646 is a wasteful number, since it uses less digits than its factorization.

28666646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14333325.

The product of its digits is 497664, while the sum is 44.

The square root of 28666646 is about 5354.1242047603. The cubic root of 28666646 is about 306.0499370280.

The spelling of 28666646 in words is "twenty-eight million, six hundred sixty-six thousand, six hundred forty-six".