28908009 has 24 divisors (see below), whose sum is σ = 46638592. Its totient is φ = 17787600.

The previous prime is 28907951. The next prime is 28908013. The reversal of 28908009 is 90080982.

It is not a de Polignac number, because 28908009 - 2²¹ = 26810857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28908029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1417 + ... + 7734.

Almost surely, 2^28908009 is an apocalyptic number.

It is an amenable number.

28908009 is a deficient number, since it is larger than the sum of its proper divisors (17730583).

28908009 is an equidigital number, since it uses as much as digits as its factorization.

28908009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9179 (or 9167 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 28908009 is about 5376.6168730904. The cubic root of 28908009 is about 306.9064815755.

The spelling of 28908009 in words is "twenty-eight million, nine hundred eight thousand, nine".