66633509 has 2 divisors, whose sum is σ = 66633510. Its totient is φ = 66633508.

The previous prime is 66633491. The next prime is 66633527. The reversal of 66633509 is 90533666.

It is a balanced prime because it is at equal distance from previous prime (66633491) and next prime (66633527).

It can be written as a sum of positive squares in only one way, i.e., 52780225 + 13853284 = 7265^2 + 3722^2 .

It is a cyclic number.

It is not a de Polignac number, because 66633509 - 2⁸ = 66633253 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 (66632509) 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, 33316754 + 33316755.

It is an arithmetic number, because the mean of its divisors is an integer number (33316755).

Almost surely, 2^66633509 is an apocalyptic number.

It is an amenable number.

66633509 is a deficient number, since it is larger than the sum of its proper divisors (1).

66633509 is an equidigital number, since it uses as much as digits as its factorization.

66633509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 87480, while the sum is 38.

The square root of 66633509 is about 8162.9350726317. The cubic root of 66633509 is about 405.4128980148.

The spelling of 66633509 in words is "sixty-six million, six hundred thirty-three thousand, five hundred nine".