2543743661 has 2 divisors, whose sum is σ = 2543743662. Its totient is φ = 2543743660.

The previous prime is 2543743633. The next prime is 2543743703. The reversal of 2543743661 is 1663473452.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1656001636 + 887742025 = 40694^2 + 29795^2 .

It is a cyclic number.

It is not a de Polignac number, because 2543743661 - 2³⁰ = 1470001837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2543743061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1271871830 + 1271871831.

It is an arithmetic number, because the mean of its divisors is an integer number (1271871831).

Almost surely, 2^2543743661 is an apocalyptic number.

It is an amenable number.

2543743661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2543743661 is an equidigital number, since it uses as much as digits as its factorization.

2543743661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 41.

The square root of 2543743661 is about 50435.5396620280. The cubic root of 2543743661 is about 1365.0789867839.

The spelling of 2543743661 in words is "two billion, five hundred forty-three million, seven hundred forty-three thousand, six hundred sixty-one".