28478939 has 2 divisors, whose sum is σ = 28478940. Its totient is φ = 28478938.

The previous prime is 28478921. The next prime is 28478951. The reversal of 28478939 is 93987482.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28478939 - 2⁸ = 28478683 is a prime.

It is a super-2 number, since 2×28478939² = 1622099933131442, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28478959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14239469 + 14239470.

It is an arithmetic number, because the mean of its divisors is an integer number (14239470).

Almost surely, 2^28478939 is an apocalyptic number.

28478939 is a deficient number, since it is larger than the sum of its proper divisors (1).

28478939 is an equidigital number, since it uses as much as digits as its factorization.

28478939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 50.

The square root of 28478939 is about 5336.5662180844. The cubic root of 28478939 is about 305.3804765290.

The spelling of 28478939 in words is "twenty-eight million, four hundred seventy-eight thousand, nine hundred thirty-nine".