66737609 has 2 divisors, whose sum is σ = 66737610. Its totient is φ = 66737608.

The previous prime is 66737581. The next prime is 66737617. The reversal of 66737609 is 90673766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64048009 + 2689600 = 8003^2 + 1640^2 .

It is a cyclic number.

It is not a de Polignac number, because 66737609 - 2⁸ = 66737353 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 66737609.

It is not a weakly prime, because it can be changed into another prime (66737639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33368804 + 33368805.

It is an arithmetic number, because the mean of its divisors is an integer number (33368805).

Almost surely, 2^66737609 is an apocalyptic number.

It is an amenable number.

66737609 is a deficient number, since it is larger than the sum of its proper divisors (1).

66737609 is an equidigital number, since it uses as much as digits as its factorization.

66737609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 285768, while the sum is 44.

The square root of 66737609 is about 8169.3089671036. The cubic root of 66737609 is about 405.6239105845.

The spelling of 66737609 in words is "sixty-six million, seven hundred thirty-seven thousand, six hundred nine".