667406807321 has 2 divisors, whose sum is σ = 667406807322. Its totient is φ = 667406807320.

The previous prime is 667406807317. The next prime is 667406807357. The reversal of 667406807321 is 123708604766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 594757152025 + 72649655296 = 771205^2 + 269536^2 .

It is a cyclic number.

It is not a de Polignac number, because 667406807321 - 2² = 667406807317 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 667406807321.

It is not a weakly prime, because it can be changed into another prime (667406804321) by changing a digit.

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 as a sum of consecutive naturals, namely, 333703403660 + 333703403661.

It is an arithmetic number, because the mean of its divisors is an integer number (333703403661).

Almost surely, 2^667406807321 is an apocalyptic number.

It is an amenable number.

667406807321 is a deficient number, since it is larger than the sum of its proper divisors (1).

667406807321 is an equidigital number, since it uses as much as digits as its factorization.

667406807321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2032128, while the sum is 50.

The spelling of 667406807321 in words is "six hundred sixty-seven billion, four hundred six million, eight hundred seven thousand, three hundred twenty-one".