28643729 has 2 divisors, whose sum is σ = 28643730. Its totient is φ = 28643728.

The previous prime is 28643711. The next prime is 28643731. The reversal of 28643729 is 92734682.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23261329 + 5382400 = 4823^2 + 2320^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28643729 is a prime.

It is a super-2 number, since 2×28643729² = 1640926422050882, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 28643731, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (28643749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14321864 + 14321865.

It is an arithmetic number, because the mean of its divisors is an integer number (14321865).

Almost surely, 2^28643729 is an apocalyptic number.

It is an amenable number.

28643729 is a deficient number, since it is larger than the sum of its proper divisors (1).

28643729 is an equidigital number, since it uses as much as digits as its factorization.

28643729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 41.

The square root of 28643729 is about 5351.9836509466. The cubic root of 28643729 is about 305.9683600361.

The spelling of 28643729 in words is "twenty-eight million, six hundred forty-three thousand, seven hundred twenty-nine".