66840663629 has 2 divisors, whose sum is σ = 66840663630. Its totient is φ = 66840663628.

The previous prime is 66840663619. The next prime is 66840663667. The reversal of 66840663629 is 92636604866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45845233225 + 20995430404 = 214115^2 + 144898^2 .

It is a cyclic number.

It is not a de Polignac number, because 66840663629 - 2²⁰ = 66839615053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66840663619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33420331814 + 33420331815.

It is an arithmetic number, because the mean of its divisors is an integer number (33420331815).

Almost surely, 2^66840663629 is an apocalyptic number.

It is an amenable number.

66840663629 is a deficient number, since it is larger than the sum of its proper divisors (1).

66840663629 is an equidigital number, since it uses as much as digits as its factorization.

66840663629 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13436928, while the sum is 56.

The spelling of 66840663629 in words is "sixty-six billion, eight hundred forty million, six hundred sixty-three thousand, six hundred twenty-nine".