28765643 has 2 divisors, whose sum is σ = 28765644. Its totient is φ = 28765642.

The previous prime is 28765621. The next prime is 28765657. The reversal of 28765643 is 34656782.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28765643 - 2¹⁶ = 28700107 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28765643.

It is not a weakly prime, because it can be changed into another prime (28765603) 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, 14382821 + 14382822.

It is an arithmetic number, because the mean of its divisors is an integer number (14382822).

Almost surely, 2^28765643 is an apocalyptic number.

28765643 is a deficient number, since it is larger than the sum of its proper divisors (1).

28765643 is an equidigital number, since it uses as much as digits as its factorization.

28765643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 41.

The square root of 28765643 is about 5363.3611662837. The cubic root of 28765643 is about 306.4018351357.

The spelling of 28765643 in words is "twenty-eight million, seven hundred sixty-five thousand, six hundred forty-three".