28001329 has 4 divisors (see below), whose sum is σ = 29648484. Its totient is φ = 26354176.

The previous prime is 28001321. The next prime is 28001353. The reversal of 28001329 is 92310082.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7507600 + 20493729 = 2740^2 + 4527^2 .

It is a cyclic number.

It is not a de Polignac number, because 28001329 - 2³ = 28001321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28001321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 823552 + ... + 823585.

It is an arithmetic number, because the mean of its divisors is an integer number (7412121).

Almost surely, 2^28001329 is an apocalyptic number.

It is an amenable number.

28001329 is a deficient number, since it is larger than the sum of its proper divisors (1647155).

28001329 is a wasteful number, since it uses less digits than its factorization.

28001329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1647154.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 28001329 is about 5291.6281993352. The cubic root of 28001329 is about 303.6637014291.

The spelling of 28001329 in words is "twenty-eight million, one thousand, three hundred twenty-nine".