2505566661 has 16 divisors (see below), whose sum is σ = 3713794560. Its totient is φ = 1492148160.

The previous prime is 2505566627. The next prime is 2505566671. The reversal of 2505566661 is 1666655052.

It is not a de Polignac number, because 2505566661 - 2⁷ = 2505566533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2505566671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1035006 + ... + 1037423.

It is an arithmetic number, because the mean of its divisors is an integer number (232112160).

Almost surely, 2^2505566661 is an apocalyptic number.

It is an amenable number.

2505566661 is a deficient number, since it is larger than the sum of its proper divisors (1208227899).

2505566661 is a wasteful number, since it uses less digits than its factorization.

2505566661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2072476.

The product of its (nonzero) digits is 324000, while the sum is 42.

The square root of 2505566661 is about 50055.6356567370. The cubic root of 2505566661 is about 1358.2154110568.

The spelling of 2505566661 in words is "two billion, five hundred five million, five hundred sixty-six thousand, six hundred sixty-one".