28003021 has 2 divisors, whose sum is σ = 28003022. Its totient is φ = 28003020.

The previous prime is 28003007. The next prime is 28003037. The reversal of 28003021 is 12030082.

It is a happy number.

It is an a-pointer prime, because the next prime (28003037) can be obtained adding 28003021 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27678121 + 324900 = 5261^2 + 570^2 .

It is a cyclic number.

It is not a de Polignac number, because 28003021 - 2⁹ = 28002509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28002986 and 28003004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28003421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14001510 + 14001511.

It is an arithmetic number, because the mean of its divisors is an integer number (14001511).

Almost surely, 2^28003021 is an apocalyptic number.

It is an amenable number.

28003021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28003021 is an equidigital number, since it uses as much as digits as its factorization.

28003021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 28003021 is about 5291.7880720981. The cubic root of 28003021 is about 303.6698176702.

The spelling of 28003021 in words is "twenty-eight million, three thousand, twenty-one".