66555900955566 has 48 divisors (see below), whose sum is σ = 157486630848768. Its totient is φ = 20146315971600.

The previous prime is 66555900955561. The next prime is 66555900955589.

66555900955566 is a `hidden beast` number, since 6 + 6 + 5 + 5 + 5 + 9 + 0 + 0 + 9 + 55 + 566 = 666.

66555900955566 is nontrivially palindromic in base 10.

It is a super-3 number, since 3×66555900955566³ (a number of 42 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 66555900955494 and 66555900955503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66555900955561) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 184309696 + ... + 184670451.

It is an arithmetic number, because the mean of its divisors is an integer number (3280971476016).

Almost surely, 2^{66555900955566} is an apocalyptic number.

66555900955566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66555900955566 is an abundant number, since it is smaller than the sum of its proper divisors (90930729893202).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66555900955566 is a wasteful number, since it uses less digits than its factorization.

66555900955566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368981077 (or 368981074 counting only the distinct ones).

The product of its (nonzero) digits is 1640250000, while the sum is 72.

The spelling of 66555900955566 in words is "sixty-six trillion, five hundred fifty-five billion, nine hundred million, nine hundred fifty-five thousand, five hundred sixty-six".