256566413 has 4 divisors (see below), whose sum is σ = 257386428. Its totient is φ = 255746400.

The previous prime is 256566407. The next prime is 256566421. The reversal of 256566413 is 314665652.

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 131171209 + 125395204 = 11453^2 + 11198^2 .

It is a cyclic number.

It is not a de Polignac number, because 256566413 - 2¹⁰ = 256565389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256566433) 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, 409538 + ... + 410163.

It is an arithmetic number, because the mean of its divisors is an integer number (64346607).

Almost surely, 2^256566413 is an apocalyptic number.

It is an amenable number.

256566413 is a deficient number, since it is larger than the sum of its proper divisors (820015).

256566413 is an equidigital number, since it uses as much as digits as its factorization.

256566413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820014.

The product of its digits is 129600, while the sum is 38.

The square root of 256566413 is about 16017.6906263044. The cubic root of 256566413 is about 635.4283698948.

The spelling of 256566413 in words is "two hundred fifty-six million, five hundred sixty-six thousand, four hundred thirteen".