28205857 has 2 divisors, whose sum is σ = 28205858. Its totient is φ = 28205856.

The previous prime is 28205819. The next prime is 28205897. The reversal of 28205857 is 75850282.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28132416 + 73441 = 5304^2 + 271^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28205857 is a prime.

It is not a weakly prime, because it can be changed into another prime (28205897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14102928 + 14102929.

It is an arithmetic number, because the mean of its divisors is an integer number (14102929).

Almost surely, 2^28205857 is an apocalyptic number.

It is an amenable number.

28205857 is a deficient number, since it is larger than the sum of its proper divisors (1).

28205857 is an equidigital number, since it uses as much as digits as its factorization.

28205857 is an evil number, because the sum of its binary digits is even.

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

The square root of 28205857 is about 5310.9186587633. The cubic root of 28205857 is about 304.4012512302.

The spelling of 28205857 in words is "twenty-eight million, two hundred five thousand, eight hundred fifty-seven".