66997967 has 2 divisors, whose sum is σ = 66997968. Its totient is φ = 66997966.

The previous prime is 66997949. The next prime is 66997979. The reversal of 66997967 is 76979966.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66997967 - 2¹⁴ = 66981583 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66997937) 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, 33498983 + 33498984.

It is an arithmetic number, because the mean of its divisors is an integer number (33498984).

Almost surely, 2^66997967 is an apocalyptic number.

66997967 is a deficient number, since it is larger than the sum of its proper divisors (1).

66997967 is an equidigital number, since it uses as much as digits as its factorization.

66997967 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7715736, while the sum is 59.

The square root of 66997967 is about 8185.2285856902. The cubic root of 66997967 is about 406.1507019795.

The spelling of 66997967 in words is "sixty-six million, nine hundred ninety-seven thousand, nine hundred sixty-seven".