28168639 has 2 divisors, whose sum is σ = 28168640. Its totient is φ = 28168638.

The previous prime is 28168633. The next prime is 28168661. The reversal of 28168639 is 93686182.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28168639 - 2³ = 28168631 is a prime.

It is a super-2 number, since 2×28168639² = 1586944446224642, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28168595 and 28168604.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28168631) 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, 14084319 + 14084320.

It is an arithmetic number, because the mean of its divisors is an integer number (14084320).

Almost surely, 2^28168639 is an apocalyptic number.

28168639 is a deficient number, since it is larger than the sum of its proper divisors (1).

28168639 is an equidigital number, since it uses as much as digits as its factorization.

28168639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 43.

The square root of 28168639 is about 5307.4135885570. The cubic root of 28168639 is about 304.2673051443.

The spelling of 28168639 in words is "twenty-eight million, one hundred sixty-eight thousand, six hundred thirty-nine".