28390321 has 2 divisors, whose sum is σ = 28390322. Its totient is φ = 28390320.

The previous prime is 28390301. The next prime is 28390337. The reversal of 28390321 is 12309382.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27709696 + 680625 = 5264^2 + 825^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28390321 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28390321.

It is not a weakly prime, because it can be changed into another prime (28390301) 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, 14195160 + 14195161.

It is an arithmetic number, because the mean of its divisors is an integer number (14195161).

Almost surely, 2^28390321 is an apocalyptic number.

It is an amenable number.

28390321 is a deficient number, since it is larger than the sum of its proper divisors (1).

28390321 is an equidigital number, since it uses as much as digits as its factorization.

28390321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 28390321 is about 5328.2568444098. The cubic root of 28390321 is about 305.0633962995.

The spelling of 28390321 in words is "twenty-eight million, three hundred ninety thousand, three hundred twenty-one".