66550609 has 2 divisors, whose sum is σ = 66550610. Its totient is φ = 66550608.

The previous prime is 66550577. The next prime is 66550619. The reversal of 66550609 is 90605566.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37552384 + 28998225 = 6128^2 + 5385^2 .

It is a cyclic number.

It is not a de Polignac number, because 66550609 - 2⁵ = 66550577 is a prime.

It is not a weakly prime, because it can be changed into another prime (66550619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33275304 + 33275305.

It is an arithmetic number, because the mean of its divisors is an integer number (33275305).

Almost surely, 2^66550609 is an apocalyptic number.

It is an amenable number.

66550609 is a deficient number, since it is larger than the sum of its proper divisors (1).

66550609 is an equidigital number, since it uses as much as digits as its factorization.

66550609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48600, while the sum is 37.

The square root of 66550609 is about 8157.8556618759. The cubic root of 66550609 is about 405.2447009762.

The spelling of 66550609 in words is "sixty-six million, five hundred fifty thousand, six hundred nine".