28042309 has 4 divisors (see below), whose sum is σ = 29518240. Its totient is φ = 26566380.

The previous prime is 28042307. The next prime is 28042349. The reversal of 28042309 is 90324082.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28042309 - 2¹ = 28042307 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28042307) 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 in 3 ways as a sum of consecutive naturals, for example, 737937 + ... + 737974.

It is an arithmetic number, because the mean of its divisors is an integer number (7379560).

Almost surely, 2^28042309 is an apocalyptic number.

It is an amenable number.

28042309 is a deficient number, since it is larger than the sum of its proper divisors (1475931).

28042309 is a wasteful number, since it uses less digits than its factorization.

28042309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1475930.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 28042309 is about 5295.4989377773. The cubic root of 28042309 is about 303.8117666958.

The spelling of 28042309 in words is "twenty-eight million, forty-two thousand, three hundred nine".