1666555 has 16 divisors (see below), whose sum is σ = 2206944. Its totient is φ = 1198080.

The previous prime is 1666541. The next prime is 1666559. The reversal of 1666555 is 5556661.

It is not a de Polignac number, because 1666555 - 2⁵ = 1666523 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1666555.

It is not an unprimeable number, because it can be changed into a prime (1666559) 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, 8539 + ... + 8731.

It is an arithmetic number, because the mean of its divisors is an integer number (137934).

2^1666555 is an apocalyptic number.

1666555 is a deficient number, since it is larger than the sum of its proper divisors (540389).

1666555 is a wasteful number, since it uses less digits than its factorization.

1666555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366.

The product of its digits is 27000, while the sum is 34.

The square root of 1666555 is about 1290.9511996973. The cubic root of 1666555 is about 118.5604621811.

The spelling of 1666555 in words is "one million, six hundred sixty-six thousand, five hundred fifty-five".