2566451561 has 4 divisors (see below), whose sum is σ = 2609950800. Its totient is φ = 2522952324.

The previous prime is 2566451557. The next prime is 2566451579. The reversal of 2566451561 is 1651546652.

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 2566451561 - 2² = 2566451557 is a prime.

It is a super-2 number, since 2×2566451561² = 13173347229918673442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2566451501) by changing a digit.

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, 21749531 + ... + 21749648.

It is an arithmetic number, because the mean of its divisors is an integer number (652487700).

Almost surely, 2^2566451561 is an apocalyptic number.

It is an amenable number.

2566451561 is a deficient number, since it is larger than the sum of its proper divisors (43499239).

2566451561 is an equidigital number, since it uses as much as digits as its factorization.

2566451561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43499238.

The product of its digits is 216000, while the sum is 41.

The square root of 2566451561 is about 50660.1575303512. The cubic root of 2566451561 is about 1369.1289614738.

The spelling of 2566451561 in words is "two billion, five hundred sixty-six million, four hundred fifty-one thousand, five hundred sixty-one".