28443281 has 2 divisors, whose sum is σ = 28443282. Its totient is φ = 28443280.

The previous prime is 28443277. The next prime is 28443307. The reversal of 28443281 is 18234482.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14753281 + 13690000 = 3841^2 + 3700^2 .

It is a cyclic number.

It is not a de Polignac number, because 28443281 - 2² = 28443277 is a prime.

It is a super-2 number, since 2×28443281² = 1618040468089922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28443221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14221640 + 14221641.

It is an arithmetic number, because the mean of its divisors is an integer number (14221641).

Almost surely, 2^28443281 is an apocalyptic number.

It is an amenable number.

28443281 is a deficient number, since it is larger than the sum of its proper divisors (1).

28443281 is an equidigital number, since it uses as much as digits as its factorization.

28443281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12288, while the sum is 32.

The square root of 28443281 is about 5333.2242593013. The cubic root of 28443281 is about 305.2529693801.

The spelling of 28443281 in words is "twenty-eight million, four hundred forty-three thousand, two hundred eighty-one".