28128313 has 2 divisors, whose sum is σ = 28128314. Its totient is φ = 28128312.

The previous prime is 28128307. The next prime is 28128329. The reversal of 28128313 is 31382182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21641104 + 6487209 = 4652^2 + 2547^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28128313 is a prime.

It is not a weakly prime, because it can be changed into another prime (28128343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14064156 + 14064157.

It is an arithmetic number, because the mean of its divisors is an integer number (14064157).

Almost surely, 2^28128313 is an apocalyptic number.

It is an amenable number.

28128313 is a deficient number, since it is larger than the sum of its proper divisors (1).

28128313 is an equidigital number, since it uses as much as digits as its factorization.

28128313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 28.

The square root of 28128313 is about 5303.6132023367. The cubic root of 28128313 is about 304.1220402492.

It can be divided in two parts, 28128 and 313, that added together give a triangular number (28441 = T₂₃₈).

The spelling of 28128313 in words is "twenty-eight million, one hundred twenty-eight thousand, three hundred thirteen".