1668218748509 has 4 divisors (see below), whose sum is σ = 1668534764160. Its totient is φ = 1667902732860.

The previous prime is 1668218748473. The next prime is 1668218748533. The reversal of 1668218748509 is 9058478128661.

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 not a de Polignac number, because 1668218748509 - 2²⁰ = 1668217699933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668218748809) 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, 157999907 + ... + 158010464.

It is an arithmetic number, because the mean of its divisors is an integer number (417133691040).

Almost surely, 2^{1668218748509} is an apocalyptic number.

It is an amenable number.

1668218748509 is a deficient number, since it is larger than the sum of its proper divisors (316015651).

1668218748509 is an equidigital number, since it uses as much as digits as its factorization.

1668218748509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316015650.

The product of its (nonzero) digits is 46448640, while the sum is 65.

The spelling of 1668218748509 in words is "one trillion, six hundred sixty-eight billion, two hundred eighteen million, seven hundred forty-eight thousand, five hundred nine".