28384721 has 2 divisors, whose sum is σ = 28384722. Its totient is φ = 28384720.

The previous prime is 28384711. The next prime is 28384753. The reversal of 28384721 is 12748382.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21520321 + 6864400 = 4639^2 + 2620^2 .

It is a cyclic number.

It is not a de Polignac number, because 28384721 - 2¹⁰ = 28383697 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28384711) 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, 14192360 + 14192361.

It is an arithmetic number, because the mean of its divisors is an integer number (14192361).

Almost surely, 2^28384721 is an apocalyptic number.

It is an amenable number.

28384721 is a deficient number, since it is larger than the sum of its proper divisors (1).

28384721 is an equidigital number, since it uses as much as digits as its factorization.

28384721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21504, while the sum is 35.

The square root of 28384721 is about 5327.7313183005. The cubic root of 28384721 is about 305.0433370293.

The spelling of 28384721 in words is "twenty-eight million, three hundred eighty-four thousand, seven hundred twenty-one".