28427821 has 2 divisors, whose sum is σ = 28427822. Its totient is φ = 28427820.

The previous prime is 28427813. The next prime is 28427843. The reversal of 28427821 is 12872482.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28238596 + 189225 = 5314^2 + 435^2 .

It is a cyclic number.

It is not a de Polignac number, because 28427821 - 2³ = 28427813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28427921) 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, 14213910 + 14213911.

It is an arithmetic number, because the mean of its divisors is an integer number (14213911).

Almost surely, 2^28427821 is an apocalyptic number.

It is an amenable number.

28427821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28427821 is an equidigital number, since it uses as much as digits as its factorization.

28427821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14336, while the sum is 34.

The square root of 28427821 is about 5331.7746576539. The cubic root of 28427821 is about 305.1976538419.

The spelling of 28427821 in words is "twenty-eight million, four hundred twenty-seven thousand, eight hundred twenty-one".