66656767 has 2 divisors, whose sum is σ = 66656768. Its totient is φ = 66656766.

The previous prime is 66656749. The next prime is 66656791. The reversal of 66656767 is 76765666.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66656767 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66656767.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66656797) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33328383 + 33328384.

It is an arithmetic number, because the mean of its divisors is an integer number (33328384).

Almost surely, 2^66656767 is an apocalyptic number.

66656767 is a deficient number, since it is larger than the sum of its proper divisors (1).

66656767 is an equidigital number, since it uses as much as digits as its factorization.

66656767 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1905120, while the sum is 49.

The square root of 66656767 is about 8164.3595584712. The cubic root of 66656767 is about 405.4600614539.

The spelling of 66656767 in words is "sixty-six million, six hundred fifty-six thousand, seven hundred sixty-seven".