28828021 has 2 divisors, whose sum is σ = 28828022. Its totient is φ = 28828020.

The previous prime is 28828003. The next prime is 28828031. The reversal of 28828021 is 12082882.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15100996 + 13727025 = 3886^2 + 3705^2 .

It is a cyclic number.

It is not a de Polignac number, because 28828021 - 2⁵ = 28827989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28828031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14414010 + 14414011.

It is an arithmetic number, because the mean of its divisors is an integer number (14414011).

Almost surely, 2^28828021 is an apocalyptic number.

It is an amenable number.

28828021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28828021 is an equidigital number, since it uses as much as digits as its factorization.

28828021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4096, while the sum is 31.

The square root of 28828021 is about 5369.1732138198. The cubic root of 28828021 is about 306.6231516444.

The spelling of 28828021 in words is "twenty-eight million, eight hundred twenty-eight thousand, twenty-one".