28775009 has 4 divisors (see below), whose sum is σ = 28809216. Its totient is φ = 28740804.

The previous prime is 28774997. The next prime is 28775017. The reversal of 28775009 is 90057782.

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 a de Polignac number, because none of the positive numbers 2^k-28775009 is a prime.

It is a super-2 number, since 2×28775009² = 1656002285900162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28775059) 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, 15809 + ... + 17534.

It is an arithmetic number, because the mean of its divisors is an integer number (7202304).

Almost surely, 2^28775009 is an apocalyptic number.

It is an amenable number.

28775009 is a deficient number, since it is larger than the sum of its proper divisors (34207).

28775009 is an equidigital number, since it uses as much as digits as its factorization.

28775009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34206.

The product of its (nonzero) digits is 35280, while the sum is 38.

The square root of 28775009 is about 5364.2342417161. The cubic root of 28775009 is about 306.4350860082.

The spelling of 28775009 in words is "twenty-eight million, seven hundred seventy-five thousand, nine".