2566643 has 4 divisors (see below), whose sum is σ = 2717640. Its totient is φ = 2415648.

The previous prime is 2566637. The next prime is 2566651. The reversal of 2566643 is 3466652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2566643 - 2²⁰ = 1518067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2566633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75473 + ... + 75506.

It is an arithmetic number, because the mean of its divisors is an integer number (679410).

2^2566643 is an apocalyptic number.

2566643 is a deficient number, since it is larger than the sum of its proper divisors (150997).

2566643 is a wasteful number, since it uses less digits than its factorization.

2566643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150996.

The product of its digits is 25920, while the sum is 32.

The square root of 2566643 is about 1602.0745925206. The cubic root of 2566643 is about 136.9163003049.

Subtracting 2566643 from its reverse (3466652), we obtain a palindrome (900009).

The spelling of 2566643 in words is "two million, five hundred sixty-six thousand, six hundred forty-three".