28249909 has 4 divisors (see below), whose sum is σ = 28350016. Its totient is φ = 28149804.

The previous prime is 28249891. The next prime is 28249919. The reversal of 28249909 is 90994282.

It is a happy number.

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 28249909 - 2⁵ = 28249877 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 (28249919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49629 + ... + 50194.

It is an arithmetic number, because the mean of its divisors is an integer number (7087504).

Almost surely, 2^28249909 is an apocalyptic number.

It is an amenable number.

28249909 is a deficient number, since it is larger than the sum of its proper divisors (100107).

28249909 is an equidigital number, since it uses as much as digits as its factorization.

28249909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100106.

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 28249909 is about 5315.0643458005. The cubic root of 28249909 is about 304.5596404255.

The spelling of 28249909 in words is "twenty-eight million, two hundred forty-nine thousand, nine hundred nine".