28640243 has 2 divisors, whose sum is σ = 28640244. Its totient is φ = 28640242.

The previous prime is 28640237. The next prime is 28640273. The reversal of 28640243 is 34204682.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28640243 - 2¹⁸ = 28378099 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28640203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14320121 + 14320122.

It is an arithmetic number, because the mean of its divisors is an integer number (14320122).

Almost surely, 2^28640243 is an apocalyptic number.

28640243 is a deficient number, since it is larger than the sum of its proper divisors (1).

28640243 is an equidigital number, since it uses as much as digits as its factorization.

28640243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 29.

The square root of 28640243 is about 5351.6579673966. The cubic root of 28640243 is about 305.9559472089.

The spelling of 28640243 in words is "twenty-eight million, six hundred forty thousand, two hundred forty-three".