66561412133 has 2 divisors, whose sum is σ = 66561412134. Its totient is φ = 66561412132.

The previous prime is 66561412117. The next prime is 66561412243. The reversal of 66561412133 is 33121416566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34253866084 + 32307546049 = 185078^2 + 179743^2 .

It is a cyclic number.

It is not a de Polignac number, because 66561412133 - 2⁴ = 66561412117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66561412033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33280706066 + 33280706067.

It is an arithmetic number, because the mean of its divisors is an integer number (33280706067).

Almost surely, 2^66561412133 is an apocalyptic number.

It is an amenable number.

66561412133 is a deficient number, since it is larger than the sum of its proper divisors (1).

66561412133 is an equidigital number, since it uses as much as digits as its factorization.

66561412133 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 38.

Adding to 66561412133 its reverse (33121416566), we get a palindrome (99682828699).

The spelling of 66561412133 in words is "sixty-six billion, five hundred sixty-one million, four hundred twelve thousand, one hundred thirty-three".