28307689 has 2 divisors, whose sum is σ = 28307690. Its totient is φ = 28307688.

The previous prime is 28307651. The next prime is 28307711. The reversal of 28307689 is 98670382.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26347689 + 1960000 = 5133^2 + 1400^2 .

It is a cyclic number.

It is not a de Polignac number, because 28307689 - 2⁹ = 28307177 is a prime.

It is not a weakly prime, because it can be changed into another prime (28307639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14153844 + 14153845.

It is an arithmetic number, because the mean of its divisors is an integer number (14153845).

Almost surely, 2^28307689 is an apocalyptic number.

It is an amenable number.

28307689 is a deficient number, since it is larger than the sum of its proper divisors (1).

28307689 is an equidigital number, since it uses as much as digits as its factorization.

28307689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 28307689 is about 5320.4970632451. The cubic root of 28307689 is about 304.7671392908.

The spelling of 28307689 in words is "twenty-eight million, three hundred seven thousand, six hundred eighty-nine".