28111609 has 4 divisors (see below), whose sum is σ = 28797300. Its totient is φ = 27425920.

The previous prime is 28111607. The next prime is 28111613. The reversal of 28111609 is 90611182.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1040400 + 27071209 = 1020^2 + 5203^2 .

It is a cyclic number.

It is not a de Polignac number, because 28111609 - 2¹ = 28111607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28111607) 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, 342784 + ... + 342865.

It is an arithmetic number, because the mean of its divisors is an integer number (7199325).

Almost surely, 2^28111609 is an apocalyptic number.

It is an amenable number.

28111609 is a deficient number, since it is larger than the sum of its proper divisors (685691).

28111609 is an equidigital number, since it uses as much as digits as its factorization.

28111609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685690.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 28111609 is about 5302.0381929971. The cubic root of 28111609 is about 304.0618273659.

The spelling of 28111609 in words is "twenty-eight million, one hundred eleven thousand, six hundred nine".