5651566661 has 32 divisors (see below), whose sum is σ = 6398028000. Its totient is φ = 4956069888.

The previous prime is 5651566651. The next prime is 5651566673. The reversal of 5651566661 is 1666651565.

It can be written as a sum of positive squares in 16 ways, for example, as 4501068100 + 1150498561 = 67090^2 + 33919^2 .

It is a cyclic number.

It is not a de Polignac number, because 5651566661 - 2⁶ = 5651566597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5651566651) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13051901 + ... + 13052333.

It is an arithmetic number, because the mean of its divisors is an integer number (199938375).

Almost surely, 2^5651566661 is an apocalyptic number.

It is an amenable number.

5651566661 is a deficient number, since it is larger than the sum of its proper divisors (746461339).

5651566661 is a wasteful number, since it uses less digits than its factorization.

5651566661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 953.

The product of its digits is 972000, while the sum is 47.

The square root of 5651566661 is about 75176.9024435032. The cubic root of 5651566661 is about 1781.2421012129.

The spelling of 5651566661 in words is "five billion, six hundred fifty-one million, five hundred sixty-six thousand, six hundred sixty-one".