28638139 has 2 divisors, whose sum is σ = 28638140. Its totient is φ = 28638138.

The previous prime is 28638107. The next prime is 28638157. The reversal of 28638139 is 93183682.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28638139 - 2⁵ = 28638107 is a prime.

It is not a weakly prime, because it can be changed into another prime (28638439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14319069 + 14319070.

It is an arithmetic number, because the mean of its divisors is an integer number (14319070).

Almost surely, 2^28638139 is an apocalyptic number.

28638139 is a deficient number, since it is larger than the sum of its proper divisors (1).

28638139 is an equidigital number, since it uses as much as digits as its factorization.

28638139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 40.

The square root of 28638139 is about 5351.4613891908. The cubic root of 28638139 is about 305.9484548717.

The spelling of 28638139 in words is "twenty-eight million, six hundred thirty-eight thousand, one hundred thirty-nine".