28390009 has 8 divisors (see below), whose sum is σ = 29951840. Its totient is φ = 26834976.

The previous prime is 28390003. The next prime is 28390091. The reversal of 28390009 is 90009382.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28390009 - 2³ = 28390001 is a prime.

It is a super-2 number, since 2×28390009² = 1611985222040162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28390001) 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 7 ways as a sum of consecutive naturals, for example, 8509 + ... + 11365.

It is an arithmetic number, because the mean of its divisors is an integer number (3743980).

Almost surely, 2^28390009 is an apocalyptic number.

It is an amenable number.

28390009 is a deficient number, since it is larger than the sum of its proper divisors (1561831).

28390009 is a wasteful number, since it uses less digits than its factorization.

28390009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3399.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 28390009 is about 5328.2275664615. The cubic root of 28390009 is about 305.0622787810.

The spelling of 28390009 in words is "twenty-eight million, three hundred ninety thousand, nine".