66636513 has 10 divisors (see below), whose sum is σ = 99543554. Its totient is φ = 44424288.

The previous prime is 66636491. The next prime is 66636523. The reversal of 66636513 is 31563666.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 45319824 + 21316689 = 6732^2 + 4617^2 .

It is not a de Polignac number, because 66636513 - 2¹⁸ = 66374369 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66636523) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 411256 + ... + 411417.

Almost surely, 2^66636513 is an apocalyptic number.

It is an amenable number.

66636513 is a deficient number, since it is larger than the sum of its proper divisors (32907041).

66636513 is an equidigital number, since it uses as much as digits as its factorization.

66636513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 822685 (or 822676 counting only the distinct ones).

The product of its digits is 58320, while the sum is 36.

The square root of 66636513 is about 8163.1190730014. The cubic root of 66636513 is about 405.4189902550.

The spelling of 66636513 in words is "sixty-six million, six hundred thirty-six thousand, five hundred thirteen".