2663690681 has 2 divisors, whose sum is σ = 2663690682. Its totient is φ = 2663690680.

The previous prime is 2663690671. The next prime is 2663690723. The reversal of 2663690681 is 1860963662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2663076025 + 614656 = 51605^2 + 784^2 .

It is a cyclic number.

It is not a de Polignac number, because 2663690681 - 2²² = 2659496377 is a prime.

It is a super-2 number, since 2×2663690681² = 14190496088092487522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2663690621) 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, 1331845340 + 1331845341.

It is an arithmetic number, because the mean of its divisors is an integer number (1331845341).

Almost surely, 2^2663690681 is an apocalyptic number.

It is an amenable number.

2663690681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2663690681 is an equidigital number, since it uses as much as digits as its factorization.

2663690681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 559872, while the sum is 47.

The square root of 2663690681 is about 51610.9550483228. The cubic root of 2663690681 is about 1386.2064983803.

The spelling of 2663690681 in words is "two billion, six hundred sixty-three million, six hundred ninety thousand, six hundred eighty-one".