1216105015666 has 8 divisors (see below), whose sum is σ = 1824329629404. Its totient is φ = 607995139200.

The previous prime is 1216105015639. The next prime is 1216105015681. The reversal of 1216105015666 is 6665105016121.

It can be written as a sum of positive squares in 2 ways, for example, as 1061046265041 + 155058750625 = 1030071^2 + 393775^2 .

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

It is a super-2 number, since 2×1216105015666² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28657815 + ... + 28700218.

Almost surely, 2^{1216105015666} is an apocalyptic number.

1216105015666 is a deficient number, since it is larger than the sum of its proper divisors (608224613738).

1216105015666 is a wasteful number, since it uses less digits than its factorization.

1216105015666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57368636.

The product of its (nonzero) digits is 64800, while the sum is 40.

The spelling of 1216105015666 in words is "one trillion, two hundred sixteen billion, one hundred five million, fifteen thousand, six hundred sixty-six".