28572809 has 2 divisors, whose sum is σ = 28572810. Its totient is φ = 28572808.

The previous prime is 28572787. The next prime is 28572811. The reversal of 28572809 is 90827582.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19404025 + 9168784 = 4405^2 + 3028^2 .

It is a cyclic number.

It is not a de Polignac number, because 28572809 - 2¹² = 28568713 is a prime.

Together with 28572811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28572839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14286404 + 14286405.

It is an arithmetic number, because the mean of its divisors is an integer number (14286405).

Almost surely, 2^28572809 is an apocalyptic number.

It is an amenable number.

28572809 is a deficient number, since it is larger than the sum of its proper divisors (1).

28572809 is an equidigital number, since it uses as much as digits as its factorization.

28572809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 28572809 is about 5345.3539639579. The cubic root of 28572809 is about 305.7156321246.

The spelling of 28572809 in words is "twenty-eight million, five hundred seventy-two thousand, eight hundred nine".