5555555 is nontrivially palindromic in base 10.
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is a nude number because it is divisible by every one of its digits.
5555555 is a nontrivial repdigit in base 10.
It is a plaindrome in base 10.
It is a nialpdrome in base 10.
It is a zygodrome in base 10.
It is a congruent number.
It is an unprimeable number.
It is an upside-down number.
Almost surely, 25555555 is an apocalyptic number.
5555555 is a wasteful number, since it uses less digits than its factorization.
5555555 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 4893.
The square root of 5555555 is about 2357.0224861040. The cubic root of 5555555 is about 177.1097556268.
The spelling of 5555555 in words is "five million, five hundred fifty-five thousand, five hundred fifty-five".