660642786481 has 2 divisors, whose sum is σ = 660642786482. Its totient is φ = 660642786480.

The previous prime is 660642786439. The next prime is 660642786521. The reversal of 660642786481 is 184687246066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 534347842081 + 126294944400 = 730991^2 + 355380^2 .

It is a cyclic number.

It is not a de Polignac number, because 660642786481 - 2¹¹ = 660642784433 is a prime.

It is a super-2 number, since 2×660642786481² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (660642786581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330321393240 + 330321393241.

It is an arithmetic number, because the mean of its divisors is an integer number (330321393241).

Almost surely, 2^660642786481 is an apocalyptic number.

It is an amenable number.

660642786481 is a deficient number, since it is larger than the sum of its proper divisors (1).

660642786481 is an equidigital number, since it uses as much as digits as its factorization.

660642786481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18579456, while the sum is 58.

The spelling of 660642786481 in words is "six hundred sixty billion, six hundred forty-two million, seven hundred eighty-six thousand, four hundred eighty-one".