6661586661 has 4 divisors (see below), whose sum is σ = 8882115552. Its totient is φ = 4441057772.

The previous prime is 6661586653. The next prime is 6661586677. The reversal of 6661586661 is 1666851666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6661586661 - 2³ = 6661586653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6661586681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1110264441 + ... + 1110264446.

It is an arithmetic number, because the mean of its divisors is an integer number (2220528888).

Almost surely, 2^6661586661 is an apocalyptic number.

It is an amenable number.

6661586661 is a deficient number, since it is larger than the sum of its proper divisors (2220528891).

6661586661 is a wasteful number, since it uses less digits than its factorization.

6661586661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2220528890.

The product of its digits is 1866240, while the sum is 51.

The square root of 6661586661 is about 81618.5436098930. The cubic root of 6661586661 is about 1881.5938894507.

The spelling of 6661586661 in words is "six billion, six hundred sixty-one million, five hundred eighty-six thousand, six hundred sixty-one".