66997949 has 2 divisors, whose sum is σ = 66997950. Its totient is φ = 66997948.

The previous prime is 66997939. The next prime is 66997967. The reversal of 66997949 is 94979966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37295449 + 29702500 = 6107^2 + 5450^2 .

It is a cyclic number.

It is not a de Polignac number, because 66997949 - 2¹² = 66993853 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66997939) 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, 33498974 + 33498975.

It is an arithmetic number, because the mean of its divisors is an integer number (33498975).

Almost surely, 2^66997949 is an apocalyptic number.

It is an amenable number.

66997949 is a deficient number, since it is larger than the sum of its proper divisors (1).

66997949 is an equidigital number, since it uses as much as digits as its factorization.

66997949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6613488, while the sum is 59.

The square root of 66997949 is about 8185.2274861484. The cubic root of 66997949 is about 406.1506656067.

The spelling of 66997949 in words is "sixty-six million, nine hundred ninety-seven thousand, nine hundred forty-nine".