2128609 has 6 divisors (see below), whose sum is σ = 2476194. Its totient is φ = 1824480.

The previous prime is 2128603. The next prime is 2128631. The reversal of 2128609 is 9068212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1677025 + 451584 = 1295^2 + 672^2 .

It is not a de Polignac number, because 2128609 - 2³ = 2128601 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2128601) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 21672 + ... + 21769.

It is an arithmetic number, because the mean of its divisors is an integer number (412699).

2^2128609 is an apocalyptic number.

It is an amenable number.

2128609 is a deficient number, since it is larger than the sum of its proper divisors (347585).

2128609 is an equidigital number, since it uses as much as digits as its factorization.

2128609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43455 (or 43448 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 2128609 is about 1458.9753253568. The cubic root of 2128609 is about 128.6368207625.

The spelling of 2128609 in words is "two million, one hundred twenty-eight thousand, six hundred nine".