28864421 has 2 divisors, whose sum is σ = 28864422. Its totient is φ = 28864420.

The previous prime is 28864361. The next prime is 28864499. The reversal of 28864421 is 12446882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21520321 + 7344100 = 4639^2 + 2710^2 .

It is a cyclic number.

It is not a de Polignac number, because 28864421 - 2¹⁴ = 28848037 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28864321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14432210 + 14432211.

It is an arithmetic number, because the mean of its divisors is an integer number (14432211).

Almost surely, 2^28864421 is an apocalyptic number.

It is an amenable number.

28864421 is a deficient number, since it is larger than the sum of its proper divisors (1).

28864421 is an equidigital number, since it uses as much as digits as its factorization.

28864421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24576, while the sum is 35.

The square root of 28864421 is about 5372.5618656280. The cubic root of 28864421 is about 306.7521510007.

The spelling of 28864421 in words is "twenty-eight million, eight hundred sixty-four thousand, four hundred twenty-one".