6661165566505 has 16 divisors (see below), whose sum is σ = 8414373214080. Its totient is φ = 5048300719872.

The previous prime is 6661165566491. The next prime is 6661165566529. The reversal of 6661165566505 is 5056655611666.

It is a de Polignac number, because none of the positive numbers 2^k-6661165566505 is a prime.

It is a super-2 number, since 2×6661165566505² (a number of 26 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 6661165566505.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1903857 + ... + 4116673.

It is an arithmetic number, because the mean of its divisors is an integer number (525898325880).

Almost surely, 2^{6661165566505} is an apocalyptic number.

It is an amenable number.

6661165566505 is a deficient number, since it is larger than the sum of its proper divisors (1753207647575).

6661165566505 is a wasteful number, since it uses less digits than its factorization.

6661165566505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2244528.

The product of its (nonzero) digits is 29160000, while the sum is 58.

The spelling of 6661165566505 in words is "six trillion, six hundred sixty-one billion, one hundred sixty-five million, five hundred sixty-six thousand, five hundred five".