1666120216 has 8 divisors (see below), whose sum is σ = 3123975420. Its totient is φ = 833060104.

The previous prime is 1666120213. The next prime is 1666120229. The reversal of 1666120216 is 6120216661.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666120213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104132506 + ... + 104132521.

Almost surely, 2^1666120216 is an apocalyptic number.

It is an amenable number.

1666120216 is a deficient number, since it is larger than the sum of its proper divisors (1457855204).

1666120216 is a wasteful number, since it uses less digits than its factorization.

1666120216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208265033 (or 208265029 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 1666120216 is about 40818.1358712031. The cubic root of 1666120216 is about 1185.5015095514.

Adding to 1666120216 its reverse (6120216661), we get a palindrome (7786336877).

The spelling of 1666120216 in words is "one billion, six hundred sixty-six million, one hundred twenty thousand, two hundred sixteen".