7728389 has 2 divisors, whose sum is σ = 7728390. Its totient is φ = 7728388.

The previous prime is 7728373. The next prime is 7728397. The reversal of 7728389 is 9838277.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6980164 + 748225 = 2642^2 + 865^2 .

It is an emirp because it is prime and its reverse (9838277) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7728389 - 2⁴ = 7728373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7728349) 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, 3864194 + 3864195.

It is an arithmetic number, because the mean of its divisors is an integer number (3864195).

Almost surely, 2^7728389 is an apocalyptic number.

It is an amenable number.

7728389 is a deficient number, since it is larger than the sum of its proper divisors (1).

7728389 is an equidigital number, since it uses as much as digits as its factorization.

7728389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 44.

The square root of 7728389 is about 2779.9980215820. The cubic root of 7728389 is about 197.7104651651.

The spelling of 7728389 in words is "seven million, seven hundred twenty-eight thousand, three hundred eighty-nine".