66943936510081 has 2 divisors, whose sum is σ = 66943936510082. Its totient is φ = 66943936510080.

The previous prime is 66943936510069. The next prime is 66943936510091. The reversal of 66943936510081 is 18001563934966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42542223553600 + 24401712956481 = 6522440^2 + 4939809^2 .

It is a cyclic number.

It is not a de Polignac number, because 66943936510081 - 2⁷ = 66943936509953 is a prime.

It is a super-2 number, since 2×66943936510081² (a number of 28 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66943936510001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33471968255040 + 33471968255041.

It is an arithmetic number, because the mean of its divisors is an integer number (33471968255041).

Almost surely, 2^{66943936510081} is an apocalyptic number.

It is an amenable number.

66943936510081 is a deficient number, since it is larger than the sum of its proper divisors (1).

66943936510081 is an equidigital number, since it uses as much as digits as its factorization.

66943936510081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25194240, while the sum is 61.

The spelling of 66943936510081 in words is "sixty-six trillion, nine hundred forty-three billion, nine hundred thirty-six million, five hundred ten thousand, eighty-one".