28780289 has 2 divisors, whose sum is σ = 28780290. Its totient is φ = 28780288.

The previous prime is 28780261. The next prime is 28780313. The reversal of 28780289 is 98208782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25170289 + 3610000 = 5017^2 + 1900^2 .

It is a cyclic number.

It is not a de Polignac number, because 28780289 - 2¹² = 28776193 is a prime.

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 (28780249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14390144 + 14390145.

It is an arithmetic number, because the mean of its divisors is an integer number (14390145).

Almost surely, 2^28780289 is an apocalyptic number.

It is an amenable number.

28780289 is a deficient number, since it is larger than the sum of its proper divisors (1).

28780289 is an equidigital number, since it uses as much as digits as its factorization.

28780289 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 129024, while the sum is 44.

The square root of 28780289 is about 5364.7263676724. The cubic root of 28780289 is about 306.4538277145.

The spelling of 28780289 in words is "twenty-eight million, seven hundred eighty thousand, two hundred eighty-nine".