2566621 has 4 divisors (see below), whose sum is σ = 2577600. Its totient is φ = 2555644.

The previous prime is 2566601. The next prime is 2566633. The reversal of 2566621 is 1266652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2566621 - 2⁵ = 2566589 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2566621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2566601) 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, 5131 + ... + 5608.

It is an arithmetic number, because the mean of its divisors is an integer number (644400).

2^2566621 is an apocalyptic number.

It is an amenable number.

2566621 is a deficient number, since it is larger than the sum of its proper divisors (10979).

2566621 is a wasteful number, since it uses less digits than its factorization.

2566621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10978.

The product of its digits is 4320, while the sum is 28.

The square root of 2566621 is about 1602.0677264086. The cubic root of 2566621 is about 136.9159091108.

The spelling of 2566621 in words is "two million, five hundred sixty-six thousand, six hundred twenty-one".