66439320671 has 2 divisors, whose sum is σ = 66439320672. Its totient is φ = 66439320670.

The previous prime is 66439320643. The next prime is 66439320677. The reversal of 66439320671 is 17602393466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66439320671 - 2¹⁸ = 66439058527 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66439320677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33219660335 + 33219660336.

It is an arithmetic number, because the mean of its divisors is an integer number (33219660336).

Almost surely, 2^66439320671 is an apocalyptic number.

66439320671 is a deficient number, since it is larger than the sum of its proper divisors (1).

66439320671 is an equidigital number, since it uses as much as digits as its factorization.

66439320671 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 979776, while the sum is 47.

The spelling of 66439320671 in words is "sixty-six billion, four hundred thirty-nine million, three hundred twenty thousand, six hundred seventy-one".