66509189 has 2 divisors, whose sum is σ = 66509190. Its totient is φ = 66509188.

The previous prime is 66509173. The next prime is 66509203. The reversal of 66509189 is 98190566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63760225 + 2748964 = 7985^2 + 1658^2 .

It is a cyclic number.

It is not a de Polignac number, because 66509189 - 2⁴ = 66509173 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 (66509119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33254594 + 33254595.

It is an arithmetic number, because the mean of its divisors is an integer number (33254595).

Almost surely, 2^66509189 is an apocalyptic number.

It is an amenable number.

66509189 is a deficient number, since it is larger than the sum of its proper divisors (1).

66509189 is an equidigital number, since it uses as much as digits as its factorization.

66509189 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 66509189 is about 8155.3166094273. The cubic root of 66509189 is about 405.1606109919.

The spelling of 66509189 in words is "sixty-six million, five hundred nine thousand, one hundred eighty-nine".