660721663097 has 2 divisors, whose sum is σ = 660721663098. Its totient is φ = 660721663096.

The previous prime is 660721663081. The next prime is 660721663157. The reversal of 660721663097 is 790366127066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 656976712681 + 3744950416 = 810541^2 + 61196^2 .

It is a cyclic number.

It is not a de Polignac number, because 660721663097 - 2⁴ = 660721663081 is a prime.

It is not a weakly prime, because it can be changed into another prime (660721663037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330360831548 + 330360831549.

It is an arithmetic number, because the mean of its divisors is an integer number (330360831549).

Almost surely, 2^660721663097 is an apocalyptic number.

It is an amenable number.

660721663097 is a deficient number, since it is larger than the sum of its proper divisors (1).

660721663097 is an equidigital number, since it uses as much as digits as its factorization.

660721663097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3429216, while the sum is 53.

The spelling of 660721663097 in words is "six hundred sixty billion, seven hundred twenty-one million, six hundred sixty-three thousand, ninety-seven".