28443509 has 2 divisors, whose sum is σ = 28443510. Its totient is φ = 28443508.

The previous prime is 28443497. The next prime is 28443517. The reversal of 28443509 is 90534482.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21436900 + 7006609 = 4630^2 + 2647^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28443509 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28443559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14221754 + 14221755.

It is an arithmetic number, because the mean of its divisors is an integer number (14221755).

Almost surely, 2^28443509 is an apocalyptic number.

It is an amenable number.

28443509 is a deficient number, since it is larger than the sum of its proper divisors (1).

28443509 is an equidigital number, since it uses as much as digits as its factorization.

28443509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 28443509 is about 5333.2456346956. The cubic root of 28443509 is about 305.2537850091.

The spelling of 28443509 in words is "twenty-eight million, four hundred forty-three thousand, five hundred nine".