28309643 has 2 divisors, whose sum is σ = 28309644. Its totient is φ = 28309642.

The previous prime is 28309613. The next prime is 28309649. The reversal of 28309643 is 34690382.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28309643 - 2¹⁰ = 28308619 is a prime.

It is not a weakly prime, because it can be changed into another prime (28309649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14154821 + 14154822.

It is an arithmetic number, because the mean of its divisors is an integer number (14154822).

Almost surely, 2^28309643 is an apocalyptic number.

28309643 is a deficient number, since it is larger than the sum of its proper divisors (1).

28309643 is an equidigital number, since it uses as much as digits as its factorization.

28309643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 28309643 is about 5320.6806895359. The cubic root of 28309643 is about 304.7741515350.

The spelling of 28309643 in words is "twenty-eight million, three hundred nine thousand, six hundred forty-three".