28986821 has 2 divisors, whose sum is σ = 28986822. Its totient is φ = 28986820.

The previous prime is 28986817. The next prime is 28986847. The reversal of 28986821 is 12868982.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28238596 + 748225 = 5314^2 + 865^2 .

It is a cyclic number.

It is not a de Polignac number, because 28986821 - 2² = 28986817 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 (28986851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14493410 + 14493411.

It is an arithmetic number, because the mean of its divisors is an integer number (14493411).

Almost surely, 2^28986821 is an apocalyptic number.

It is an amenable number.

28986821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28986821 is an equidigital number, since it uses as much as digits as its factorization.

28986821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 110592, while the sum is 44.

The square root of 28986821 is about 5383.9410286518. The cubic root of 28986821 is about 307.1851352139.

The spelling of 28986821 in words is "twenty-eight million, nine hundred eighty-six thousand, eight hundred twenty-one".