6636656261 has 2 divisors, whose sum is σ = 6636656262. Its totient is φ = 6636656260.

The previous prime is 6636656239. The next prime is 6636656317. The reversal of 6636656261 is 1626566366.

6636656261 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5041852036 + 1594804225 = 71006^2 + 39935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6636656261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6636656561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3318328130 + 3318328131.

It is an arithmetic number, because the mean of its divisors is an integer number (3318328131).

Almost surely, 2^6636656261 is an apocalyptic number.

It is an amenable number.

6636656261 is a deficient number, since it is larger than the sum of its proper divisors (1).

6636656261 is an equidigital number, since it uses as much as digits as its factorization.

6636656261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1399680, while the sum is 47.

The square root of 6636656261 is about 81465.6753547161. The cubic root of 6636656261 is about 1879.2437222348.

The spelling of 6636656261 in words is "six billion, six hundred thirty-six million, six hundred fifty-six thousand, two hundred sixty-one".