28039639 has 2 divisors, whose sum is σ = 28039640. Its totient is φ = 28039638.

The previous prime is 28039637. The next prime is 28039651. The reversal of 28039639 is 93693082.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28039639 - 2¹ = 28039637 is a prime.

Together with 28039637, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28039631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14019819 + 14019820.

It is an arithmetic number, because the mean of its divisors is an integer number (14019820).

Almost surely, 2^28039639 is an apocalyptic number.

28039639 is a deficient number, since it is larger than the sum of its proper divisors (1).

28039639 is an equidigital number, since it uses as much as digits as its factorization.

28039639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 40.

The square root of 28039639 is about 5295.2468308852. The cubic root of 28039639 is about 303.8021240857.

The spelling of 28039639 in words is "twenty-eight million, thirty-nine thousand, six hundred thirty-nine".