28705657 has 2 divisors, whose sum is σ = 28705658. Its totient is φ = 28705656.

The previous prime is 28705631. The next prime is 28705667. The reversal of 28705657 is 75650782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27657081 + 1048576 = 5259^2 + 1024^2 .

It is a cyclic number.

It is not a de Polignac number, because 28705657 - 2⁷ = 28705529 is a prime.

It is not a weakly prime, because it can be changed into another prime (28705627) 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, 14352828 + 14352829.

It is an arithmetic number, because the mean of its divisors is an integer number (14352829).

Almost surely, 2^28705657 is an apocalyptic number.

It is an amenable number.

28705657 is a deficient number, since it is larger than the sum of its proper divisors (1).

28705657 is an equidigital number, since it uses as much as digits as its factorization.

28705657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 117600, while the sum is 40.

The square root of 28705657 is about 5357.7660456575. The cubic root of 28705657 is about 306.1887034340.

The spelling of 28705657 in words is "twenty-eight million, seven hundred five thousand, six hundred fifty-seven".