66450187081 has 2 divisors, whose sum is σ = 66450187082. Its totient is φ = 66450187080.

The previous prime is 66450187019. The next prime is 66450187093. The reversal of 66450187081 is 18078105466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63453610000 + 2996577081 = 251900^2 + 54741^2 .

It is a cyclic number.

It is not a de Polignac number, because 66450187081 - 2¹⁵ = 66450154313 is a prime.

It is a super-2 number, since 2×66450187081² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66450181081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33225093540 + 33225093541.

It is an arithmetic number, because the mean of its divisors is an integer number (33225093541).

Almost surely, 2^66450187081 is an apocalyptic number.

It is an amenable number.

66450187081 is a deficient number, since it is larger than the sum of its proper divisors (1).

66450187081 is an equidigital number, since it uses as much as digits as its factorization.

66450187081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 322560, while the sum is 46.

The spelling of 66450187081 in words is "sixty-six billion, four hundred fifty million, one hundred eighty-seven thousand, eighty-one".