66345020103521 has 2 divisors, whose sum is σ = 66345020103522. Its totient is φ = 66345020103520.

The previous prime is 66345020103493. The next prime is 66345020103553. The reversal of 66345020103521 is 12530102054366.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46381057812496 + 19963962291025 = 6810364^2 + 4468105^2 .

It is a cyclic number.

It is not a de Polignac number, because 66345020103521 - 2³⁰ = 66343946361697 is a prime.

It is not a weakly prime, because it can be changed into another prime (66345023103521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33172510051760 + 33172510051761.

It is an arithmetic number, because the mean of its divisors is an integer number (33172510051761).

Almost surely, 2^{66345020103521} is an apocalyptic number.

It is an amenable number.

66345020103521 is a deficient number, since it is larger than the sum of its proper divisors (1).

66345020103521 is an equidigital number, since it uses as much as digits as its factorization.

66345020103521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 129600, while the sum is 38.

Adding to 66345020103521 its reverse (12530102054366), we get a palindrome (78875122157887).

The spelling of 66345020103521 in words is "sixty-six trillion, three hundred forty-five billion, twenty million, one hundred three thousand, five hundred twenty-one".