1312223206666 has 4 divisors (see below), whose sum is σ = 1968334810002. Its totient is φ = 656111603332.

The previous prime is 1312223206663. The next prime is 1312223206669. The reversal of 1312223206666 is 6666023222131.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1312223206663) and next prime (1312223206669).

It can be written as a sum of positive squares in only one way, i.e., 1191863475625 + 120359731041 = 1091725^2 + 346929^2 .

It is a super-2 number, since 2×1312223206666² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1312223206663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328055801665 + ... + 328055801668.

Almost surely, 2^{1312223206666} is an apocalyptic number.

1312223206666 is a deficient number, since it is larger than the sum of its proper divisors (656111603336).

1312223206666 is an equidigital number, since it uses as much as digits as its factorization.

1312223206666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656111603335.

The product of its (nonzero) digits is 186624, while the sum is 40.

Adding to 1312223206666 its reverse (6666023222131), we get a palindrome (7978246428797).

The spelling of 1312223206666 in words is "one trillion, three hundred twelve billion, two hundred twenty-three million, two hundred six thousand, six hundred sixty-six".