66108687391 has 2 divisors, whose sum is σ = 66108687392. Its totient is φ = 66108687390.

The previous prime is 66108687373. The next prime is 66108687413. The reversal of 66108687391 is 19378680166.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66108687391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66108687311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33054343695 + 33054343696.

It is an arithmetic number, because the mean of its divisors is an integer number (33054343696).

Almost surely, 2^66108687391 is an apocalyptic number.

66108687391 is a deficient number, since it is larger than the sum of its proper divisors (1).

66108687391 is an equidigital number, since it uses as much as digits as its factorization.

66108687391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2612736, while the sum is 55.

The spelling of 66108687391 in words is "sixty-six billion, one hundred eight million, six hundred eighty-seven thousand, three hundred ninety-one".