6661773281 has 2 divisors, whose sum is σ = 6661773282. Its totient is φ = 6661773280.

The previous prime is 6661773263. The next prime is 6661773317. The reversal of 6661773281 is 1823771666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5463575056 + 1198198225 = 73916^2 + 34615^2 .

It is a cyclic number.

It is not a de Polignac number, because 6661773281 - 2³⁰ = 5588031457 is a prime.

It is a super-2 number, since 2×6661773281² = 88758446494891009922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6661778281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3330886640 + 3330886641.

It is an arithmetic number, because the mean of its divisors is an integer number (3330886641).

Almost surely, 2^6661773281 is an apocalyptic number.

It is an amenable number.

6661773281 is a deficient number, since it is larger than the sum of its proper divisors (1).

6661773281 is an equidigital number, since it uses as much as digits as its factorization.

6661773281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 508032, while the sum is 47.

The square root of 6661773281 is about 81619.6868469856. The cubic root of 6661773281 is about 1881.6114598279.

The spelling of 6661773281 in words is "six billion, six hundred sixty-one million, seven hundred seventy-three thousand, two hundred eighty-one".