28003639 has 2 divisors, whose sum is σ = 28003640. Its totient is φ = 28003638.

The previous prime is 28003637. The next prime is 28003649. The reversal of 28003639 is 93630082.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28003639 - 2¹ = 28003637 is a prime.

Together with 28003637, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 28003639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28003637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14001819 + 14001820.

It is an arithmetic number, because the mean of its divisors is an integer number (14001820).

Almost surely, 2^28003639 is an apocalyptic number.

28003639 is a deficient number, since it is larger than the sum of its proper divisors (1).

28003639 is an equidigital number, since it uses as much as digits as its factorization.

28003639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 28003639 is about 5291.8464641371. The cubic root of 28003639 is about 303.6720515549.

The spelling of 28003639 in words is "twenty-eight million, three thousand, six hundred thirty-nine".