1216441666 has 8 divisors (see below), whose sum is σ = 1990540944. Its totient is φ = 552928020.

The previous prime is 1216441661. The next prime is 1216441673. The reversal of 1216441666 is 6661446121.

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

It is not an unprimeable number, because it can be changed into a prime (1216441661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27646380 + ... + 27646423.

It is an arithmetic number, because the mean of its divisors is an integer number (248817618).

Almost surely, 2^1216441666 is an apocalyptic number.

1216441666 is a deficient number, since it is larger than the sum of its proper divisors (774099278).

1216441666 is a wasteful number, since it uses less digits than its factorization.

1216441666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55292816.

The product of its digits is 41472, while the sum is 37.

The square root of 1216441666 is about 34877.5237939851. The cubic root of 1216441666 is about 1067.4898699739.

Adding to 1216441666 its reverse (6661446121), we get a palindrome (7877887787).

The spelling of 1216441666 in words is "one billion, two hundred sixteen million, four hundred forty-one thousand, six hundred sixty-six".