28001609 has 2 divisors, whose sum is σ = 28001610. Its totient is φ = 28001608.

The previous prime is 28001593. The next prime is 28001621. The reversal of 28001609 is 90610082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25351225 + 2650384 = 5035^2 + 1628^2 .

It is a cyclic number.

It is not a de Polignac number, because 28001609 - 2⁴ = 28001593 is a prime.

It is not a weakly prime, because it can be changed into another prime (28001009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14000804 + 14000805.

It is an arithmetic number, because the mean of its divisors is an integer number (14000805).

Almost surely, 2^28001609 is an apocalyptic number.

It is an amenable number.

28001609 is a deficient number, since it is larger than the sum of its proper divisors (1).

28001609 is an equidigital number, since it uses as much as digits as its factorization.

28001609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 28001609 is about 5291.6546561543. The cubic root of 28001609 is about 303.6647135900.

The spelling of 28001609 in words is "twenty-eight million, one thousand, six hundred nine".