5661550666 has 16 divisors (see below), whose sum is σ = 8634079080. Its totient is φ = 2783551680.

The previous prime is 5661550651. The next prime is 5661550693. The reversal of 5661550666 is 6660551665.

It can be written as a sum of positive squares in 4 ways, for example, as 4177683225 + 1483867441 = 64635^2 + 38521^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 815040 + ... + 821956.

Almost surely, 2^5661550666 is an apocalyptic number.

5661550666 is a deficient number, since it is larger than the sum of its proper divisors (2972528414).

5661550666 is a wasteful number, since it uses less digits than its factorization.

5661550666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13689.

The product of its (nonzero) digits is 972000, while the sum is 46.

The square root of 5661550666 is about 75243.2765501344. The cubic root of 5661550666 is about 1782.2903927203.

Subtracting 5661550666 from its reverse (6660551665), we obtain a palindrome (999000999).

The spelling of 5661550666 in words is "five billion, six hundred sixty-one million, five hundred fifty thousand, six hundred sixty-six".