667376531266721 has 2 divisors, whose sum is σ = 667376531266722. Its totient is φ = 667376531266720.

The previous prime is 667376531266691. The next prime is 667376531266769. The reversal of 667376531266721 is 127662135673766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 416843476395025 + 250533054871696 = 20416745^2 + 15828236^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667376531266721 is a prime.

It is not a weakly prime, because it can be changed into another prime (667376531266771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333688265633360 + 333688265633361.

It is an arithmetic number, because the mean of its divisors is an integer number (333688265633361).

Almost surely, 2^{667376531266721} is an apocalyptic number.

It is an amenable number.

667376531266721 is a deficient number, since it is larger than the sum of its proper divisors (1).

667376531266721 is an equidigital number, since it uses as much as digits as its factorization.

667376531266721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480090240, while the sum is 68.

The spelling of 667376531266721 in words is "six hundred sixty-seven trillion, three hundred seventy-six billion, five hundred thirty-one million, two hundred sixty-six thousand, seven hundred twenty-one".