1666216 has 8 divisors (see below), whose sum is σ = 3124170. Its totient is φ = 833104.

The previous prime is 1666213. The next prime is 1666237. The reversal of 1666216 is 6126661.

It can be written as a sum of positive squares in only one way, i.e., 1664100 + 2116 = 1290^2 + 46^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (1666211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104131 + ... + 104146.

2^1666216 is an apocalyptic number.

It is an amenable number.

1666216 is a deficient number, since it is larger than the sum of its proper divisors (1457954).

1666216 is a wasteful number, since it uses less digits than its factorization.

1666216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208283 (or 208279 counting only the distinct ones).

The product of its digits is 2592, while the sum is 28.

The square root of 1666216 is about 1290.8198944857. The cubic root of 1666216 is about 118.5524226980.

The spelling of 1666216 in words is "one million, six hundred sixty-six thousand, two hundred sixteen".