66731321 has 2 divisors, whose sum is σ = 66731322. Its totient is φ = 66731320.

The previous prime is 66731317. The next prime is 66731339. The reversal of 66731321 is 12313766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57214096 + 9517225 = 7564^2 + 3085^2 .

It is a cyclic number.

It is not a de Polignac number, because 66731321 - 2² = 66731317 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66731381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33365660 + 33365661.

It is an arithmetic number, because the mean of its divisors is an integer number (33365661).

Almost surely, 2^66731321 is an apocalyptic number.

It is an amenable number.

66731321 is a deficient number, since it is larger than the sum of its proper divisors (1).

66731321 is an equidigital number, since it uses as much as digits as its factorization.

66731321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 29.

The square root of 66731321 is about 8168.9241029648. The cubic root of 66731321 is about 405.6111709249.

The spelling of 66731321 in words is "sixty-six million, seven hundred thirty-one thousand, three hundred twenty-one".