28786909 has 4 divisors (see below), whose sum is σ = 29456416. Its totient is φ = 28117404.

The previous prime is 28786907. The next prime is 28786913. The reversal of 28786909 is 90968782.

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 28786909 - 2¹ = 28786907 is a prime.

It is a super-2 number, since 2×28786909² = 1657372259548562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28786907) 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, 334689 + ... + 334774.

It is an arithmetic number, because the mean of its divisors is an integer number (7364104).

Almost surely, 2^28786909 is an apocalyptic number.

It is an amenable number.

28786909 is a deficient number, since it is larger than the sum of its proper divisors (669507).

28786909 is an equidigital number, since it uses as much as digits as its factorization.

28786909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 669506.

The product of its (nonzero) digits is 435456, while the sum is 49.

The square root of 28786909 is about 5365.3433254546. The cubic root of 28786909 is about 306.4773226003.

The spelling of 28786909 in words is "twenty-eight million, seven hundred eighty-six thousand, nine hundred nine".