28068639 has 4 divisors (see below), whose sum is σ = 37424856. Its totient is φ = 18712424.

The previous prime is 28068629. The next prime is 28068679. The reversal of 28068639 is 93686082.

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

It is a cyclic number.

It is not a de Polignac number, because 28068639 - 2⁹ = 28068127 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28068639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28068619) 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, 4678104 + ... + 4678109.

It is an arithmetic number, because the mean of its divisors is an integer number (9356214).

Almost surely, 2^28068639 is an apocalyptic number.

28068639 is a deficient number, since it is larger than the sum of its proper divisors (9356217).

28068639 is an equidigital number, since it uses as much as digits as its factorization.

28068639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9356216.

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 28068639 is about 5297.9844280632. The cubic root of 28068639 is about 303.9068237931.

The spelling of 28068639 in words is "twenty-eight million, sixty-eight thousand, six hundred thirty-nine".