166643659508 has 6 divisors (see below), whose sum is σ = 291626404146. Its totient is φ = 83321829752.

The previous prime is 166643659453. The next prime is 166643659571. The reversal of 166643659508 is 805956346661.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 89824885264 + 76818774244 = 299708^2 + 277162^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20830457435 + ... + 20830457442.

It is an arithmetic number, because the mean of its divisors is an integer number (48604400691).

Almost surely, 2^166643659508 is an apocalyptic number.

It is an amenable number.

166643659508 is a deficient number, since it is larger than the sum of its proper divisors (124982744638).

166643659508 is a wasteful number, since it uses less digits than its factorization.

166643659508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41660914881 (or 41660914879 counting only the distinct ones).

The product of its (nonzero) digits is 27993600, while the sum is 59.

The spelling of 166643659508 in words is "one hundred sixty-six billion, six hundred forty-three million, six hundred fifty-nine thousand, five hundred eight".