1666155506 has 8 divisors (see below), whose sum is σ = 2509960284. Its totient is φ = 829502080.

The previous prime is 1666155497. The next prime is 1666155521. The reversal of 1666155506 is 6055516661.

It can be written as a sum of positive squares in 2 ways, for example, as 1278420025 + 387735481 = 35755^2 + 19691^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1787255 + ... + 1788186.

Almost surely, 2^1666155506 is an apocalyptic number.

1666155506 is a deficient number, since it is larger than the sum of its proper divisors (843804778).

1666155506 is a wasteful number, since it uses less digits than its factorization.

1666155506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3575676.

The product of its (nonzero) digits is 162000, while the sum is 41.

The square root of 1666155506 is about 40818.5681522515. The cubic root of 1666155506 is about 1185.5098795062.

It can be divided in two parts, 1666155 and 506, that added together give a palindrome (1666661).

The spelling of 1666155506 in words is "one billion, six hundred sixty-six million, one hundred fifty-five thousand, five hundred six".