1001666506 has 8 divisors (see below), whose sum is σ = 1512584100. Its totient is φ = 497471808.

The previous prime is 1001666473. The next prime is 1001666521. The reversal of 1001666506 is 6056661001.

It can be written as a sum of positive squares in 2 ways, for example, as 847683225 + 153983281 = 29115^2 + 12409^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1680351 + ... + 1680946.

Almost surely, 2^1001666506 is an apocalyptic number.

1001666506 is a deficient number, since it is larger than the sum of its proper divisors (510917594).

1001666506 is a wasteful number, since it uses less digits than its factorization.

1001666506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3361448.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 1001666506 is about 31649.1154062795. The cubic root of 1001666506 is about 1000.5551937029. Note that the first 3 decimals are identical.

The spelling of 1001666506 in words is "one billion, one million, six hundred sixty-six thousand, five hundred six".