6661655555505 has 32 divisors (see below), whose sum is σ = 10868839372800. Its totient is φ = 3483147640512.

The previous prime is 6661655555501. The next prime is 6661655555507. The reversal of 6661655555505 is 5055555561666.

It is a happy number.

It is not a de Polignac number, because 6661655555505 - 2² = 6661655555501 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6661655555501) 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, 9930375 + ... + 10579964.

It is an arithmetic number, because the mean of its divisors is an integer number (339651230400).

Almost surely, 2^{6661655555505} is an apocalyptic number.

It is an amenable number.

6661655555505 is a deficient number, since it is larger than the sum of its proper divisors (4207183817295).

6661655555505 is a wasteful number, since it uses less digits than its factorization.

6661655555505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20510773.

The product of its (nonzero) digits is 101250000, while the sum is 60.

The spelling of 6661655555505 in words is "six trillion, six hundred sixty-one billion, six hundred fifty-five million, five hundred fifty-five thousand, five hundred five".