28822721 has 2 divisors, whose sum is σ = 28822722. Its totient is φ = 28822720.

The previous prime is 28822711. The next prime is 28822727. The reversal of 28822721 is 12722882.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27709696 + 1113025 = 5264^2 + 1055^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28822721 is a prime.

It is a super-3 number, since 3×28822721³ (a number of 23 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (28822727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14411360 + 14411361.

It is an arithmetic number, because the mean of its divisors is an integer number (14411361).

Almost surely, 2^28822721 is an apocalyptic number.

It is an amenable number.

28822721 is a deficient number, since it is larger than the sum of its proper divisors (1).

28822721 is an equidigital number, since it uses as much as digits as its factorization.

28822721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7168, while the sum is 32.

The square root of 28822721 is about 5368.6796328334. The cubic root of 28822721 is about 306.6043597162.

The spelling of 28822721 in words is "twenty-eight million, eight hundred twenty-two thousand, seven hundred twenty-one".