28515139 has 2 divisors, whose sum is σ = 28515140. Its totient is φ = 28515138.

The previous prime is 28515119. The next prime is 28515167. The reversal of 28515139 is 93151582.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28515139 - 2⁵ = 28515107 is a prime.

It is a super-2 number, since 2×28515139² = 1626226304378642, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28515119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14257569 + 14257570.

It is an arithmetic number, because the mean of its divisors is an integer number (14257570).

Almost surely, 2^28515139 is an apocalyptic number.

28515139 is a deficient number, since it is larger than the sum of its proper divisors (1).

28515139 is an equidigital number, since it uses as much as digits as its factorization.

28515139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10800, while the sum is 34.

The square root of 28515139 is about 5339.9568350315. The cubic root of 28515139 is about 305.5098129554.

The spelling of 28515139 in words is "twenty-eight million, five hundred fifteen thousand, one hundred thirty-nine".