28292821 has 2 divisors, whose sum is σ = 28292822. Its totient is φ = 28292820.

The previous prime is 28292807. The next prime is 28292851. The reversal of 28292821 is 12829282.

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., 28196100 + 96721 = 5310^2 + 311^2 .

It is a cyclic number.

It is not a de Polignac number, because 28292821 - 2¹⁵ = 28260053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28292851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14146410 + 14146411.

It is an arithmetic number, because the mean of its divisors is an integer number (14146411).

Almost surely, 2^28292821 is an apocalyptic number.

It is an amenable number.

28292821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28292821 is an equidigital number, since it uses as much as digits as its factorization.

28292821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9216, while the sum is 34.

The square root of 28292821 is about 5319.0996418567. The cubic root of 28292821 is about 304.7137725020.

The spelling of 28292821 in words is "twenty-eight million, two hundred ninety-two thousand, eight hundred twenty-one".