2566135661 has 8 divisors (see below), whose sum is σ = 2592235800. Its totient is φ = 2540082240.

The previous prime is 2566135631. The next prime is 2566135681. The reversal of 2566135661 is 1665316652.

It can be written as a sum of positive squares in 4 ways, for example, as 965655625 + 1600480036 = 31075^2 + 40006^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2566135661 - 2¹⁴ = 2566119277 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2566135631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104555 + ... + 126743.

It is an arithmetic number, because the mean of its divisors is an integer number (324029475).

Almost surely, 2^2566135661 is an apocalyptic number.

It is an amenable number.

2566135661 is a deficient number, since it is larger than the sum of its proper divisors (26100139).

2566135661 is a wasteful number, since it uses less digits than its factorization.

2566135661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23359.

The product of its digits is 194400, while the sum is 41.

The square root of 2566135661 is about 50657.0395996450. The cubic root of 2566135661 is about 1369.0727846118.

The spelling of 2566135661 in words is "two billion, five hundred sixty-six million, one hundred thirty-five thousand, six hundred sixty-one".