28128469 has 2 divisors, whose sum is σ = 28128470. Its totient is φ = 28128468.

The previous prime is 28128467. The next prime is 28128487. The reversal of 28128469 is 96482182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20593444 + 7535025 = 4538^2 + 2745^2 .

It is a cyclic number.

It is not a de Polignac number, because 28128469 - 2¹ = 28128467 is a prime.

It is a super-2 number, since 2×28128469² = 1582421536567922, which contains 22 as substring.

Together with 28128467, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28128467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14064234 + 14064235.

It is an arithmetic number, because the mean of its divisors is an integer number (14064235).

Almost surely, 2^28128469 is an apocalyptic number.

It is an amenable number.

28128469 is a deficient number, since it is larger than the sum of its proper divisors (1).

28128469 is an equidigital number, since it uses as much as digits as its factorization.

28128469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 40.

The square root of 28128469 is about 5303.6279092712. The cubic root of 28128469 is about 304.1226024698.

The spelling of 28128469 in words is "twenty-eight million, one hundred twenty-eight thousand, four hundred sixty-nine".