1216665574321 has 4 divisors (see below), whose sum is σ = 1255912850944. Its totient is φ = 1177418297700.

The previous prime is 1216665574231. The next prime is 1216665574343. The reversal of 1216665574321 is 1234755666121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216665574321 is a prime.

It is a super-2 number, since 2×1216665574321² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216665574391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19623638265 + ... + 19623638326.

It is an arithmetic number, because the mean of its divisors is an integer number (313978212736).

Almost surely, 2^{1216665574321} is an apocalyptic number.

It is an amenable number.

1216665574321 is a deficient number, since it is larger than the sum of its proper divisors (39247276623).

1216665574321 is an equidigital number, since it uses as much as digits as its factorization.

1216665574321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39247276622.

The product of its digits is 1814400, while the sum is 49.

The spelling of 1216665574321 in words is "one trillion, two hundred sixteen billion, six hundred sixty-five million, five hundred seventy-four thousand, three hundred twenty-one".