28303021 has 2 divisors, whose sum is σ = 28303022. Its totient is φ = 28303020.

The previous prime is 28303019. The next prime is 28303057. The reversal of 28303021 is 12030382.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22610025 + 5692996 = 4755^2 + 2386^2 .

It is a cyclic number.

It is not a de Polignac number, because 28303021 - 2¹ = 28303019 is a prime.

Together with 28303019, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 28303021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28303081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14151510 + 14151511.

It is an arithmetic number, because the mean of its divisors is an integer number (14151511).

Almost surely, 2^28303021 is an apocalyptic number.

It is an amenable number.

28303021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28303021 is an equidigital number, since it uses as much as digits as its factorization.

28303021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 28303021 is about 5320.0583643415. The cubic root of 28303021 is about 304.7503861133.

The spelling of 28303021 in words is "twenty-eight million, three hundred three thousand, twenty-one".