28272509 has 2 divisors, whose sum is σ = 28272510. Its totient is φ = 28272508.

The previous prime is 28272499. The next prime is 28272533. The reversal of 28272509 is 90527282.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19404025 + 8868484 = 4405^2 + 2978^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28272509 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 (28274509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14136254 + 14136255.

It is an arithmetic number, because the mean of its divisors is an integer number (14136255).

Almost surely, 2^28272509 is an apocalyptic number.

It is an amenable number.

28272509 is a deficient number, since it is larger than the sum of its proper divisors (1).

28272509 is an equidigital number, since it uses as much as digits as its factorization.

28272509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 28272509 is about 5317.1899533494. The cubic root of 28272509 is about 304.6408349431.

The spelling of 28272509 in words is "twenty-eight million, two hundred seventy-two thousand, five hundred nine".