2566420561 has 4 divisors (see below), whose sum is σ = 2567911792. Its totient is φ = 2564929332.

The previous prime is 2566420559. The next prime is 2566420567. The reversal of 2566420561 is 1650246652.

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 2566420561 - 2¹ = 2566420559 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 2566420561.

It is not an unprimeable number, because it can be changed into a prime (2566420567) 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, 743031 + ... + 746476.

It is an arithmetic number, because the mean of its divisors is an integer number (641977948).

Almost surely, 2^2566420561 is an apocalyptic number.

It is an amenable number.

2566420561 is a deficient number, since it is larger than the sum of its proper divisors (1491231).

2566420561 is a wasteful number, since it uses less digits than its factorization.

2566420561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1491230.

The product of its (nonzero) digits is 86400, while the sum is 37.

The square root of 2566420561 is about 50659.8515690680. The cubic root of 2566420561 is about 1369.1234489120.

It can be divided in two parts, 25664 and 20561, that added together give a square (46225 = 215²).

The spelling of 2566420561 in words is "two billion, five hundred sixty-six million, four hundred twenty thousand, five hundred sixty-one".