6656011605661 has 4 divisors (see below), whose sum is σ = 7261103569824. Its totient is φ = 6050919641500.

The previous prime is 6656011605647. The next prime is 6656011605731. The reversal of 6656011605661 is 1665061106566.

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 6656011605661 - 2¹⁵ = 6656011572893 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6656011605601) 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, 302545982065 + ... + 302545982086.

It is an arithmetic number, because the mean of its divisors is an integer number (1815275892456).

Almost surely, 2^{6656011605661} is an apocalyptic number.

It is an amenable number.

6656011605661 is a deficient number, since it is larger than the sum of its proper divisors (605091964163).

6656011605661 is a wasteful number, since it uses less digits than its factorization.

6656011605661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 605091964162.

The product of its (nonzero) digits is 1166400, while the sum is 49.

The spelling of 6656011605661 in words is "six trillion, six hundred fifty-six billion, eleven million, six hundred five thousand, six hundred sixty-one".