28633639 has 4 divisors (see below), whose sum is σ = 28689120. Its totient is φ = 28578160.

The previous prime is 28633637. The next prime is 28633651. The reversal of 28633639 is 93633682.

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 28633639 - 2¹ = 28633637 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28633637) 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, 26959 + ... + 28000.

It is an arithmetic number, because the mean of its divisors is an integer number (7172280).

Almost surely, 2^28633639 is an apocalyptic number.

28633639 is a deficient number, since it is larger than the sum of its proper divisors (55481).

28633639 is an equidigital number, since it uses as much as digits as its factorization.

28633639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55480.

The product of its digits is 139968, while the sum is 40.

The square root of 28633639 is about 5351.0409267730. The cubic root of 28633639 is about 305.9324291543.

The spelling of 28633639 in words is "twenty-eight million, six hundred thirty-three thousand, six hundred thirty-nine".