28006681 has 2 divisors, whose sum is σ = 28006682. Its totient is φ = 28006680.

The previous prime is 28006679. The next prime is 28006691. The reversal of 28006681 is 18660082.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27457600 + 549081 = 5240^2 + 741^2 .

It is a cyclic number.

It is not a de Polignac number, because 28006681 - 2¹ = 28006679 is a prime.

It is a super-2 number, since 2×28006681² = 1568748361271522, which contains 22 as substring.

Together with 28006679, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28006661) 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, 14003340 + 14003341.

It is an arithmetic number, because the mean of its divisors is an integer number (14003341).

Almost surely, 2^28006681 is an apocalyptic number.

It is an amenable number.

28006681 is a deficient number, since it is larger than the sum of its proper divisors (1).

28006681 is an equidigital number, since it uses as much as digits as its factorization.

28006681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 28006681 is about 5292.1338796368. The cubic root of 28006681 is about 303.6830469942.

The spelling of 28006681 in words is "twenty-eight million, six thousand, six hundred eighty-one".