66561801742573 has 2 divisors, whose sum is σ = 66561801742574. Its totient is φ = 66561801742572.

The previous prime is 66561801742549. The next prime is 66561801742633. The reversal of 66561801742573 is 37524710816566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 33856361978884 + 32705439763689 = 5818622^2 + 5718867^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66561801742573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66561801742873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33280900871286 + 33280900871287.

It is an arithmetic number, because the mean of its divisors is an integer number (33280900871287).

Almost surely, 2^{66561801742573} is an apocalyptic number.

It is an amenable number.

66561801742573 is a deficient number, since it is larger than the sum of its proper divisors (1).

66561801742573 is an equidigital number, since it uses as much as digits as its factorization.

66561801742573 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50803200, while the sum is 61.

The spelling of 66561801742573 in words is "sixty-six trillion, five hundred sixty-one billion, eight hundred one million, seven hundred forty-two thousand, five hundred seventy-three".