13646666321 has 2 divisors, whose sum is σ = 13646666322. Its totient is φ = 13646666320.

The previous prime is 13646666287. The next prime is 13646666339. The reversal of 13646666321 is 12366664631.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7316236225 + 6330430096 = 85535^2 + 79564^2 .

It is an emirp because it is prime and its reverse (12366664631) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13646666321 - 2¹⁴ = 13646649937 is a prime.

It is not a weakly prime, because it can be changed into another prime (13646666221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6823333160 + 6823333161.

It is an arithmetic number, because the mean of its divisors is an integer number (6823333161).

Almost surely, 2^13646666321 is an apocalyptic number.

It is an amenable number.

13646666321 is a deficient number, since it is larger than the sum of its proper divisors (1).

13646666321 is an equidigital number, since it uses as much as digits as its factorization.

13646666321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 44.

The spelling of 13646666321 in words is "thirteen billion, six hundred forty-six million, six hundred sixty-six thousand, three hundred twenty-one".