28128728231 has 2 divisors, whose sum is σ = 28128728232. Its totient is φ = 28128728230.

The previous prime is 28128728227. The next prime is 28128728237. The reversal of 28128728231 is 13282782182.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28128728231 - 2² = 28128728227 is a prime.

It is a super-2 number, since 2×28128728231² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28128728237) 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, 14064364115 + 14064364116.

It is an arithmetic number, because the mean of its divisors is an integer number (14064364116).

Almost surely, 2^28128728231 is an apocalyptic number.

28128728231 is a deficient number, since it is larger than the sum of its proper divisors (1).

28128728231 is an equidigital number, since it uses as much as digits as its factorization.

28128728231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 172032, while the sum is 44.

The spelling of 28128728231 in words is "twenty-eight billion, one hundred twenty-eight million, seven hundred twenty-eight thousand, two hundred thirty-one".