66898309 has 2 divisors, whose sum is σ = 66898310. Its totient is φ = 66898308.

The previous prime is 66898301. The next prime is 66898313. The reversal of 66898309 is 90389866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63250209 + 3648100 = 7953^2 + 1910^2 .

It is a cyclic number.

It is not a de Polignac number, because 66898309 - 2³ = 66898301 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 (66898301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33449154 + 33449155.

It is an arithmetic number, because the mean of its divisors is an integer number (33449155).

Almost surely, 2^66898309 is an apocalyptic number.

It is an amenable number.

66898309 is a deficient number, since it is larger than the sum of its proper divisors (1).

66898309 is an equidigital number, since it uses as much as digits as its factorization.

66898309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 66898309 is about 8179.1386465813. The cubic root of 66898309 is about 405.9492219734.

The spelling of 66898309 in words is "sixty-six million, eight hundred ninety-eight thousand, three hundred nine".