28125709 has 2 divisors, whose sum is σ = 28125710. Its totient is φ = 28125708.

The previous prime is 28125707. The next prime is 28125731. The reversal of 28125709 is 90752182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15721225 + 12404484 = 3965^2 + 3522^2 .

It is a cyclic number.

It is not a de Polignac number, because 28125709 - 2¹ = 28125707 is a prime.

Together with 28125707, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28125707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14062854 + 14062855.

It is an arithmetic number, because the mean of its divisors is an integer number (14062855).

Almost surely, 2^28125709 is an apocalyptic number.

It is an amenable number.

28125709 is a deficient number, since it is larger than the sum of its proper divisors (1).

28125709 is an equidigital number, since it uses as much as digits as its factorization.

28125709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 28125709 is about 5303.3677036389. The cubic root of 28125709 is about 304.1126551831.

The spelling of 28125709 in words is "twenty-eight million, one hundred twenty-five thousand, seven hundred nine".