28208533021 has 2 divisors, whose sum is σ = 28208533022. Its totient is φ = 28208533020.

The previous prime is 28208533009. The next prime is 28208533033. The reversal of 28208533021 is 12033580282.

It is a balanced prime because it is at equal distance from previous prime (28208533009) and next prime (28208533033).

It can be written as a sum of positive squares in only one way, i.e., 24091385796 + 4117147225 = 155214^2 + 64165^2 .

It is a cyclic number.

It is not a de Polignac number, because 28208533021 - 2²⁷ = 28074315293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28208533061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14104266510 + 14104266511.

It is an arithmetic number, because the mean of its divisors is an integer number (14104266511).

Almost surely, 2^28208533021 is an apocalyptic number.

It is an amenable number.

28208533021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28208533021 is an equidigital number, since it uses as much as digits as its factorization.

28208533021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23040, while the sum is 34.

The spelling of 28208533021 in words is "twenty-eight billion, two hundred eight million, five hundred thirty-three thousand, twenty-one".