28601809 has 4 divisors (see below), whose sum is σ = 29524480. Its totient is φ = 27679140.

The previous prime is 28601791. The next prime is 28601813. The reversal of 28601809 is 90810682.

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, and also an emirpimes, since its reverse is a distinct semiprime: 90810682 = 2 ⋅45405341.

It is a cyclic number.

It is not a de Polignac number, because 28601809 - 2⁹ = 28601297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28601819) 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, 461289 + ... + 461350.

It is an arithmetic number, because the mean of its divisors is an integer number (7381120).

Almost surely, 2^28601809 is an apocalyptic number.

It is an amenable number.

28601809 is a deficient number, since it is larger than the sum of its proper divisors (922671).

28601809 is an equidigital number, since it uses as much as digits as its factorization.

28601809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922670.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 28601809 is about 5348.0659120845. The cubic root of 28601809 is about 305.8190259443.

The spelling of 28601809 in words is "twenty-eight million, six hundred one thousand, eight hundred nine".