2556209 has 4 divisors (see below), whose sum is σ = 2581620. Its totient is φ = 2530800.

The previous prime is 2556193. The next prime is 2556217. The reversal of 2556209 is 9026552.

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 2093809 + 462400 = 1447^2 + 680^2 .

It is a cyclic number.

It is not a de Polignac number, because 2556209 - 2⁴ = 2556193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2556259) 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, 12554 + ... + 12755.

It is an arithmetic number, because the mean of its divisors is an integer number (645405).

2^2556209 is an apocalyptic number.

It is an amenable number.

2556209 is a deficient number, since it is larger than the sum of its proper divisors (25411).

2556209 is a wasteful number, since it uses less digits than its factorization.

2556209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25410.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 2556209 is about 1598.8148735861. The cubic root of 2556209 is about 136.7305161368.

The spelling of 2556209 in words is "two million, five hundred fifty-six thousand, two hundred nine".