661558855166 has 24 divisors (see below), whose sum is σ = 1142525984184. Its totient is φ = 284881800240.

The previous prime is 661558855127. The next prime is 661558855187.

661558855166 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 661558855099 and 661558855108.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41641445 + ... + 41657328.

It is an arithmetic number, because the mean of its divisors is an integer number (47605249341).

Almost surely, 2^661558855166 is an apocalyptic number.

661558855166 is a deficient number, since it is larger than the sum of its proper divisors (480967129018).

661558855166 is a wasteful number, since it uses less digits than its factorization.

661558855166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83298824 (or 83298805 counting only the distinct ones).

The product of its digits is 51840000, while the sum is 62.

The spelling of 661558855166 in words is "six hundred sixty-one billion, five hundred fifty-eight million, eight hundred fifty-five thousand, one hundred sixty-six".