66736733673721 has 2 divisors, whose sum is σ = 66736733673722. Its totient is φ = 66736733673720.

The previous prime is 66736733673689. The next prime is 66736733673793. The reversal of 66736733673721 is 12737633763766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57502798963600 + 9233934710121 = 7583060^2 + 3038739^2 .

It is a cyclic number.

It is not a de Polignac number, because 66736733673721 - 2⁵ = 66736733673689 is a prime.

It is not a weakly prime, because it can be changed into another prime (66736733673121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33368366836860 + 33368366836861.

It is an arithmetic number, because the mean of its divisors is an integer number (33368366836861).

Almost surely, 2^{66736733673721} is an apocalyptic number.

It is an amenable number.

66736733673721 is a deficient number, since it is larger than the sum of its proper divisors (1).

66736733673721 is an equidigital number, since it uses as much as digits as its factorization.

66736733673721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 504094752, while the sum is 67.

The spelling of 66736733673721 in words is "sixty-six trillion, seven hundred thirty-six billion, seven hundred thirty-three million, six hundred seventy-three thousand, seven hundred twenty-one".