28920509 has 2 divisors, whose sum is σ = 28920510. Its totient is φ = 28920508.

The previous prime is 28920497. The next prime is 28920517. The reversal of 28920509 is 90502982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27269284 + 1651225 = 5222^2 + 1285^2 .

It is a cyclic number.

It is not a de Polignac number, because 28920509 - 2¹² = 28916413 is a prime.

It is a Chen prime.

It is equal to p_1795076 and since 28920509 and 1795076 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28920589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14460254 + 14460255.

It is an arithmetic number, because the mean of its divisors is an integer number (14460255).

Almost surely, 2^28920509 is an apocalyptic number.

It is an amenable number.

28920509 is a deficient number, since it is larger than the sum of its proper divisors (1).

28920509 is an equidigital number, since it uses as much as digits as its factorization.

28920509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 28920509 is about 5377.7791884755. The cubic root of 28920509 is about 306.9507112813.

The spelling of 28920509 in words is "twenty-eight million, nine hundred twenty thousand, five hundred nine".