66780149 has 2 divisors, whose sum is σ = 66780150. Its totient is φ = 66780148.

The previous prime is 66780137. The next prime is 66780151. The reversal of 66780149 is 94108766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46485124 + 20295025 = 6818^2 + 4505^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66780149 is a prime.

It is a Sophie Germain prime.

Together with 66780151, it forms a pair of twin primes.

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 (66780949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33390074 + 33390075.

It is an arithmetic number, because the mean of its divisors is an integer number (33390075).

Almost surely, 2^66780149 is an apocalyptic number.

It is an amenable number.

66780149 is a deficient number, since it is larger than the sum of its proper divisors (1).

66780149 is an equidigital number, since it uses as much as digits as its factorization.

66780149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 66780149 is about 8171.9121997241. The cubic root of 66780149 is about 405.7100767729.

The spelling of 66780149 in words is "sixty-six million, seven hundred eighty thousand, one hundred forty-nine".