667216072561 has 2 divisors, whose sum is σ = 667216072562. Its totient is φ = 667216072560.

The previous prime is 667216072531. The next prime is 667216072681. The reversal of 667216072561 is 165270612766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 417356052961 + 249860019600 = 646031^2 + 499860^2 .

It is a cyclic number.

It is not a de Polignac number, because 667216072561 - 2²⁹ = 666679201649 is a prime.

It is not a weakly prime, because it can be changed into another prime (667216072531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333608036280 + 333608036281.

It is an arithmetic number, because the mean of its divisors is an integer number (333608036281).

Almost surely, 2^667216072561 is an apocalyptic number.

It is an amenable number.

667216072561 is a deficient number, since it is larger than the sum of its proper divisors (1).

667216072561 is an equidigital number, since it uses as much as digits as its factorization.

667216072561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1270080, while the sum is 49.

The spelling of 667216072561 in words is "six hundred sixty-seven billion, two hundred sixteen million, seventy-two thousand, five hundred sixty-one".