2556213565 has 4 divisors (see below), whose sum is σ = 3067456284. Its totient is φ = 2044970848.

The previous prime is 2556213533. The next prime is 2556213577. The reversal of 2556213565 is 5653126552.

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 297873081 + 2258340484 = 17259^2 + 47522^2 .

It is a cyclic number.

It is not a de Polignac number, because 2556213565 - 2⁵ = 2556213533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 255621352 + ... + 255621361.

It is an arithmetic number, because the mean of its divisors is an integer number (766864071).

Almost surely, 2^2556213565 is an apocalyptic number.

It is an amenable number.

2556213565 is a deficient number, since it is larger than the sum of its proper divisors (511242719).

2556213565 is an equidigital number, since it uses as much as digits as its factorization.

2556213565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511242718.

The product of its digits is 270000, while the sum is 40.

The square root of 2556213565 is about 50559.0107201476. The cubic root of 2556213565 is about 1367.3059753000.

The spelling of 2556213565 in words is "two billion, five hundred fifty-six million, two hundred thirteen thousand, five hundred sixty-five".