28328281 has 2 divisors, whose sum is σ = 28328282. Its totient is φ = 28328280.

The previous prime is 28328257. The next prime is 28328291. The reversal of 28328281 is 18282382.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18662400 + 9665881 = 4320^2 + 3109^2 .

It is a cyclic number.

It is not a de Polignac number, because 28328281 - 2¹⁷ = 28197209 is a prime.

It is a super-2 number, since 2×28328281² = 1604983008829922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28328291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14164140 + 14164141.

It is an arithmetic number, because the mean of its divisors is an integer number (14164141).

Almost surely, 2^28328281 is an apocalyptic number.

It is an amenable number.

28328281 is a deficient number, since it is larger than the sum of its proper divisors (1).

28328281 is an equidigital number, since it uses as much as digits as its factorization.

28328281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12288, while the sum is 34.

The square root of 28328281 is about 5322.4318689862. The cubic root of 28328281 is about 304.8410207935.

The spelling of 28328281 in words is "twenty-eight million, three hundred twenty-eight thousand, two hundred eighty-one".