28728555217 has 2 divisors, whose sum is σ = 28728555218. Its totient is φ = 28728555216.

The previous prime is 28728555209. The next prime is 28728555223. The reversal of 28728555217 is 71255582782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24387194896 + 4341360321 = 156164^2 + 65889^2 .

It is a cyclic number.

It is not a de Polignac number, because 28728555217 - 2³ = 28728555209 is a prime.

It is not a weakly prime, because it can be changed into another prime (28728555257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14364277608 + 14364277609.

It is an arithmetic number, because the mean of its divisors is an integer number (14364277609).

Almost surely, 2^28728555217 is an apocalyptic number.

It is an amenable number.

28728555217 is a deficient number, since it is larger than the sum of its proper divisors (1).

28728555217 is an equidigital number, since it uses as much as digits as its factorization.

28728555217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3136000, while the sum is 52.

The spelling of 28728555217 in words is "twenty-eight billion, seven hundred twenty-eight million, five hundred fifty-five thousand, two hundred seventeen".