1663666 has 8 divisors (see below), whose sum is σ = 2502000. Its totient is φ = 829668.

The previous prime is 1663619. The next prime is 1663681. The reversal of 1663666 is 6663661.

It is a happy number.

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, 165 + ... + 1831.

It is an arithmetic number, because the mean of its divisors is an integer number (312750).

2^1663666 is an apocalyptic number.

1663666 is a deficient number, since it is larger than the sum of its proper divisors (838334).

1663666 is a wasteful number, since it uses less digits than its factorization.

1663666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2168.

The product of its digits is 23328, while the sum is 34.

The square root of 1663666 is about 1289.8317719765. The cubic root of 1663666 is about 118.4919137307.

The spelling of 1663666 in words is "one million, six hundred sixty-three thousand, six hundred sixty-six".