1666855555 has 8 divisors (see below), whose sum is σ = 2001106800. Its totient is φ = 1332897696.

The previous prime is 1666855529. The next prime is 1666855601. The reversal of 1666855555 is 5555586661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1666855555 - 2²⁹ = 1129984643 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60645 + ... + 83734.

It is an arithmetic number, because the mean of its divisors is an integer number (250138350).

Almost surely, 2^1666855555 is an apocalyptic number.

1666855555 is a deficient number, since it is larger than the sum of its proper divisors (334251245).

1666855555 is a wasteful number, since it uses less digits than its factorization.

1666855555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146693.

The product of its digits is 5400000, while the sum is 52.

The square root of 1666855555 is about 40827.1423810190. The cubic root of 1666855555 is about 1185.6758901813.

The spelling of 1666855555 in words is "one billion, six hundred sixty-six million, eight hundred fifty-five thousand, five hundred fifty-five".