28715909 has 2 divisors, whose sum is σ = 28715910. Its totient is φ = 28715908.

The previous prime is 28715849. The next prime is 28715923. The reversal of 28715909 is 90951782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19775809 + 8940100 = 4447^2 + 2990^2 .

It is a cyclic number.

It is not a de Polignac number, because 28715909 - 2⁸ = 28715653 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28715009) 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, 14357954 + 14357955.

It is an arithmetic number, because the mean of its divisors is an integer number (14357955).

Almost surely, 2^28715909 is an apocalyptic number.

It is an amenable number.

28715909 is a deficient number, since it is larger than the sum of its proper divisors (1).

28715909 is an equidigital number, since it uses as much as digits as its factorization.

28715909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 28715909 is about 5358.7227022864. The cubic root of 28715909 is about 306.2251500592.

The spelling of 28715909 in words is "twenty-eight million, seven hundred fifteen thousand, nine hundred nine".