2565855601 has 4 divisors (see below), whose sum is σ = 2584584612. Its totient is φ = 2547126592.

The previous prime is 2565855599. The next prime is 2565855619. The reversal of 2565855601 is 1065585652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1215219600 + 1350636001 = 34860^2 + 36751^2 .

It is a cyclic number.

It is not a de Polignac number, because 2565855601 - 2¹ = 2565855599 is a prime.

It is a super-2 number, since 2×2565855601² = 13167229930366142402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2565855641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9364300 + ... + 9364573.

It is an arithmetic number, because the mean of its divisors is an integer number (646146153).

Almost surely, 2^2565855601 is an apocalyptic number.

It is an amenable number.

2565855601 is a deficient number, since it is larger than the sum of its proper divisors (18729011).

2565855601 is a wasteful number, since it uses less digits than its factorization.

2565855601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18729010.

The product of its (nonzero) digits is 360000, while the sum is 43.

The square root of 2565855601 is about 50654.2752489856. The cubic root of 2565855601 is about 1369.0229773628.

The spelling of 2565855601 in words is "two billion, five hundred sixty-five million, eight hundred fifty-five thousand, six hundred one".