28383221 has 2 divisors, whose sum is σ = 28383222. Its totient is φ = 28383220.

The previous prime is 28383191. The next prime is 28383263. The reversal of 28383221 is 12238382.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16924996 + 11458225 = 4114^2 + 3385^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28383221 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28383281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14191610 + 14191611.

It is an arithmetic number, because the mean of its divisors is an integer number (14191611).

Almost surely, 2^28383221 is an apocalyptic number.

It is an amenable number.

28383221 is a deficient number, since it is larger than the sum of its proper divisors (1).

28383221 is an equidigital number, since it uses as much as digits as its factorization.

28383221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 29.

The square root of 28383221 is about 5327.5905435760. The cubic root of 28383221 is about 305.0379635625.

The spelling of 28383221 in words is "twenty-eight million, three hundred eighty-three thousand, two hundred twenty-one".