55666811866655 has 16 divisors (see below), whose sum is σ = 72879211728000. Its totient is φ = 40481457209760.

The previous prime is 55666811866639. The next prime is 55666811866657.

It is a happy number.

55666811866655 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 55666811866655 - 2⁴ = 55666811866639 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55666811866657) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43068305 + ... + 44341994.

It is an arithmetic number, because the mean of its divisors is an integer number (4554950733000).

Almost surely, 2^{55666811866655} is an apocalyptic number.

55666811866655 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

55666811866655 is a deficient number, since it is larger than the sum of its proper divisors (17212399861345).

55666811866655 is a wasteful number, since it uses less digits than its factorization.

55666811866655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87421894.

The product of its digits is 1866240000, while the sum is 74.

The spelling of 55666811866655 in words is "fifty-five trillion, six hundred sixty-six billion, eight hundred eleven million, eight hundred sixty-six thousand, six hundred fifty-five".