66129693556 has 6 divisors (see below), whose sum is σ = 115726963730. Its totient is φ = 33064846776.

The previous prime is 66129693529. The next prime is 66129693559. The reversal of 66129693556 is 65539692166.

It can be written as a sum of positive squares in only one way, i.e., 51015449956 + 15114243600 = 225866^2 + 122940^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66129693556.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66129693559) by changing a digit.

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 as a sum of consecutive naturals, namely, 8266211691 + ... + 8266211698.

Almost surely, 2^66129693556 is an apocalyptic number.

It is an amenable number.

66129693556 is a deficient number, since it is larger than the sum of its proper divisors (49597270174).

66129693556 is a wasteful number, since it uses less digits than its factorization.

66129693556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16532423393 (or 16532423391 counting only the distinct ones).

The product of its digits is 15746400, while the sum is 58.

The spelling of 66129693556 in words is "sixty-six billion, one hundred twenty-nine million, six hundred ninety-three thousand, five hundred fifty-six".