28671821 has 2 divisors, whose sum is σ = 28671822. Its totient is φ = 28671820.

The previous prime is 28671803. The next prime is 28671847. The reversal of 28671821 is 12817682.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16491721 + 12180100 = 4061^2 + 3490^2 .

It is a cyclic number.

It is not a de Polignac number, because 28671821 - 2⁶ = 28671757 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 (28671871) 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, 14335910 + 14335911.

It is an arithmetic number, because the mean of its divisors is an integer number (14335911).

Almost surely, 2^28671821 is an apocalyptic number.

It is an amenable number.

28671821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28671821 is an equidigital number, since it uses as much as digits as its factorization.

28671821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 35.

The square root of 28671821 is about 5354.6074552669. The cubic root of 28671821 is about 306.0683523102.

It can be divided in two parts, 28671 and 821, that added together give a palindrome (29492).

The spelling of 28671821 in words is "twenty-eight million, six hundred seventy-one thousand, eight hundred twenty-one".