66381861671 has 2 divisors, whose sum is σ = 66381861672. Its totient is φ = 66381861670.

The previous prime is 66381861577. The next prime is 66381861691. The reversal of 66381861671 is 17616818366.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66381861671 - 2¹⁴ = 66381845287 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66381861691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33190930835 + 33190930836.

It is an arithmetic number, because the mean of its divisors is an integer number (33190930836).

Almost surely, 2^66381861671 is an apocalyptic number.

66381861671 is a deficient number, since it is larger than the sum of its proper divisors (1).

66381861671 is an equidigital number, since it uses as much as digits as its factorization.

66381861671 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1741824, while the sum is 53.

The spelling of 66381861671 in words is "sixty-six billion, three hundred eighty-one million, eight hundred sixty-one thousand, six hundred seventy-one".