66205613 has 2 divisors, whose sum is σ = 66205614. Its totient is φ = 66205612.

The previous prime is 66205603. The next prime is 66205621. The reversal of 66205613 is 31650266.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65496649 + 708964 = 8093^2 + 842^2 .

It is a cyclic number.

It is not a de Polignac number, because 66205613 - 2⁴ = 66205597 is a prime.

It is equal to p_3907604 and since 66205613 and 3907604 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66205603) 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, 33102806 + 33102807.

It is an arithmetic number, because the mean of its divisors is an integer number (33102807).

Almost surely, 2^66205613 is an apocalyptic number.

It is an amenable number.

66205613 is a deficient number, since it is larger than the sum of its proper divisors (1).

66205613 is an equidigital number, since it uses as much as digits as its factorization.

66205613 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 66205613 is about 8136.6831694493. The cubic root of 66205613 is about 404.5432293826.

Adding to 66205613 its reverse (31650266), we get a palindrome (97855879).

The spelling of 66205613 in words is "sixty-six million, two hundred five thousand, six hundred thirteen".