28878281 has 2 divisors, whose sum is σ = 28878282. Its totient is φ = 28878280.

The previous prime is 28878251. The next prime is 28878301. The reversal of 28878281 is 18287882.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27994681 + 883600 = 5291^2 + 940^2 .

It is a cyclic number.

It is not a de Polignac number, because 28878281 - 2⁶ = 28878217 is a prime.

It is a super-2 number, since 2×28878281² = 1667910227029922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28878251) 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, 14439140 + 14439141.

It is an arithmetic number, because the mean of its divisors is an integer number (14439141).

Almost surely, 2^28878281 is an apocalyptic number.

It is an amenable number.

28878281 is a deficient number, since it is larger than the sum of its proper divisors (1).

28878281 is an equidigital number, since it uses as much as digits as its factorization.

28878281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 114688, while the sum is 44.

The square root of 28878281 is about 5373.8515982487. The cubic root of 28878281 is about 306.8012414766.

The spelling of 28878281 in words is "twenty-eight million, eight hundred seventy-eight thousand, two hundred eighty-one".