666121637535349 has 2 divisors, whose sum is σ = 666121637535350. Its totient is φ = 666121637535348.

The previous prime is 666121637535331. The next prime is 666121637535359. The reversal of 666121637535349 is 943535736121666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 625834778556100 + 40286858979249 = 25016690^2 + 6347193^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666121637535349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666121637535359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333060818767674 + 333060818767675.

It is an arithmetic number, because the mean of its divisors is an integer number (333060818767675).

Almost surely, 2^{666121637535349} is an apocalyptic number.

It is an amenable number.

666121637535349 is a deficient number, since it is larger than the sum of its proper divisors (1).

666121637535349 is an equidigital number, since it uses as much as digits as its factorization.

666121637535349 is an evil number, because the sum of its binary digits is even.

The product of its digits is 440899200, while the sum is 67.

The spelling of 666121637535349 in words is "six hundred sixty-six trillion, one hundred twenty-one billion, six hundred thirty-seven million, five hundred thirty-five thousand, three hundred forty-nine".