660344555350261 has 2 divisors, whose sum is σ = 660344555350262. Its totient is φ = 660344555350260.

The previous prime is 660344555350243. The next prime is 660344555350273. The reversal of 660344555350261 is 162053555443066.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 605425413895236 + 54919141455025 = 24605394^2 + 7410745^2 .

It is a cyclic number.

It is not a de Polignac number, because 660344555350261 - 2⁹ = 660344555349749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660344555350211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330172277675130 + 330172277675131.

It is an arithmetic number, because the mean of its divisors is an integer number (330172277675131).

Almost surely, 2^{660344555350261} is an apocalyptic number.

It is an amenable number.

660344555350261 is a deficient number, since it is larger than the sum of its proper divisors (1).

660344555350261 is an equidigital number, since it uses as much as digits as its factorization.

660344555350261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880000, while the sum is 55.

The spelling of 660344555350261 in words is "six hundred sixty trillion, three hundred forty-four billion, five hundred fifty-five million, three hundred fifty thousand, two hundred sixty-one".