2555665561 has 8 divisors (see below), whose sum is σ = 2635386624. Its totient is φ = 2477000640.

The previous prime is 2555665529. The next prime is 2555665583. The reversal of 2555665561 is 1655665552.

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 2555665561 - 2⁵ = 2555665529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2555665061) 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, 259120 + ... + 268801.

It is an arithmetic number, because the mean of its divisors is an integer number (329423328).

Almost surely, 2^2555665561 is an apocalyptic number.

It is an amenable number.

2555665561 is a deficient number, since it is larger than the sum of its proper divisors (79721063).

2555665561 is a wasteful number, since it uses less digits than its factorization.

2555665561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528071.

The product of its digits is 1350000, while the sum is 46.

The square root of 2555665561 is about 50553.5909802657. The cubic root of 2555665561 is about 1367.2082601084.

Subtracting from 2555665561 its reverse (1655665552), we obtain a palindrome (900000009).

The spelling of 2555665561 in words is "two billion, five hundred fifty-five million, six hundred sixty-five thousand, five hundred sixty-one".