67666691 has 2 divisors, whose sum is σ = 67666692. Its totient is φ = 67666690.

The previous prime is 67666639. The next prime is 67666723. The reversal of 67666691 is 19666676.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-67666691 is a prime.

It is not a weakly prime, because it can be changed into another prime (67666601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33833345 + 33833346.

It is an arithmetic number, because the mean of its divisors is an integer number (33833346).

Almost surely, 2^67666691 is an apocalyptic number.

67666691 is a deficient number, since it is larger than the sum of its proper divisors (1).

67666691 is an equidigital number, since it uses as much as digits as its factorization.

67666691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 47.

The square root of 67666691 is about 8225.9765985566. The cubic root of 67666691 is about 407.4975291857.

The spelling of 67666691 in words is "sixty-seven million, six hundred sixty-six thousand, six hundred ninety-one".