28323821 has 2 divisors, whose sum is σ = 28323822. Its totient is φ = 28323820.

The previous prime is 28323811. The next prime is 28323847. The reversal of 28323821 is 12832382.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18369796 + 9954025 = 4286^2 + 3155^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28323821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28323811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14161910 + 14161911.

It is an arithmetic number, because the mean of its divisors is an integer number (14161911).

Almost surely, 2^28323821 is an apocalyptic number.

It is an amenable number.

28323821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28323821 is an equidigital number, since it uses as much as digits as its factorization.

28323821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 29.

The square root of 28323821 is about 5322.0128710855. The cubic root of 28323821 is about 304.8250219135.

The spelling of 28323821 in words is "twenty-eight million, three hundred twenty-three thousand, eight hundred twenty-one".