667216216661 has 2 divisors, whose sum is σ = 667216216662. Its totient is φ = 667216216660.

The previous prime is 667216216649. The next prime is 667216216747. The reversal of 667216216661 is 166612612766.

667216216661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 647712697636 + 19503519025 = 804806^2 + 139655^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667216216661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667216216621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333608108330 + 333608108331.

It is an arithmetic number, because the mean of its divisors is an integer number (333608108331).

Almost surely, 2^667216216661 is an apocalyptic number.

It is an amenable number.

667216216661 is a deficient number, since it is larger than the sum of its proper divisors (1).

667216216661 is an equidigital number, since it uses as much as digits as its factorization.

667216216661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 50.

The spelling of 667216216661 in words is "six hundred sixty-seven billion, two hundred sixteen million, two hundred sixteen thousand, six hundred sixty-one".