28001321 has 2 divisors, whose sum is σ = 28001322. Its totient is φ = 28001320.

The previous prime is 28001297. The next prime is 28001353. The reversal of 28001321 is 12310082.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19678096 + 8323225 = 4436^2 + 2885^2 .

It is a cyclic number.

It is not a de Polignac number, because 28001321 - 2¹⁴ = 27984937 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28001321.

It is not a weakly prime, because it can be changed into another prime (28001621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14000660 + 14000661.

It is an arithmetic number, because the mean of its divisors is an integer number (14000661).

Almost surely, 2^28001321 is an apocalyptic number.

It is an amenable number.

28001321 is a deficient number, since it is larger than the sum of its proper divisors (1).

28001321 is an equidigital number, since it uses as much as digits as its factorization.

28001321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 28001321 is about 5291.6274434242. The cubic root of 28001321 is about 303.6636725101.

The spelling of 28001321 in words is "twenty-eight million, one thousand, three hundred twenty-one".