2556509 has 2 divisors, whose sum is σ = 2556510. Its totient is φ = 2556508.

The previous prime is 2556503. The next prime is 2556523. The reversal of 2556509 is 9056552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1562500 + 994009 = 1250^2 + 997^2 .

It is a cyclic number.

It is not a de Polignac number, because 2556509 - 2⁴ = 2556493 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2556503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1278254 + 1278255.

It is an arithmetic number, because the mean of its divisors is an integer number (1278255).

2^2556509 is an apocalyptic number.

It is an amenable number.

2556509 is a deficient number, since it is larger than the sum of its proper divisors (1).

2556509 is an equidigital number, since it uses as much as digits as its factorization.

2556509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13500, while the sum is 32.

The square root of 2556509 is about 1598.9086903260. The cubic root of 2556509 is about 136.7358648844.

The spelling of 2556509 in words is "two million, five hundred fifty-six thousand, five hundred nine".