28520857 has 2 divisors, whose sum is σ = 28520858. Its totient is φ = 28520856.

The previous prime is 28520839. The next prime is 28520867. The reversal of 28520857 is 75802582.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28472896 + 47961 = 5336^2 + 219^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28520857 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28520827) 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, 14260428 + 14260429.

It is an arithmetic number, because the mean of its divisors is an integer number (14260429).

Almost surely, 2^28520857 is an apocalyptic number.

It is an amenable number.

28520857 is a deficient number, since it is larger than the sum of its proper divisors (1).

28520857 is an equidigital number, since it uses as much as digits as its factorization.

28520857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 44800, while the sum is 37.

The square root of 28520857 is about 5340.4922057803. The cubic root of 28520857 is about 305.5302323819.

The spelling of 28520857 in words is "twenty-eight million, five hundred twenty thousand, eight hundred fifty-seven".