28780261 has 2 divisors, whose sum is σ = 28780262. Its totient is φ = 28780260.

The previous prime is 28780249. The next prime is 28780289. The reversal of 28780261 is 16208782.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17850625 + 10929636 = 4225^2 + 3306^2 .

It is a cyclic number.

It is not a de Polignac number, because 28780261 - 2¹¹ = 28778213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28780361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14390130 + 14390131.

It is an arithmetic number, because the mean of its divisors is an integer number (14390131).

Almost surely, 2^28780261 is an apocalyptic number.

It is an amenable number.

28780261 is a deficient number, since it is larger than the sum of its proper divisors (1).

28780261 is an equidigital number, since it uses as much as digits as its factorization.

28780261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 28780261 is about 5364.7237580327. The cubic root of 28780261 is about 306.4537283327.

The spelling of 28780261 in words is "twenty-eight million, seven hundred eighty thousand, two hundred sixty-one".