2543721818381 has 2 divisors, whose sum is σ = 2543721818382. Its totient is φ = 2543721818380.

The previous prime is 2543721818347. The next prime is 2543721818447. The reversal of 2543721818381 is 1838181273452.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1721517188356 + 822204630025 = 1312066^2 + 906755^2 .

It is a cyclic number.

It is not a de Polignac number, because 2543721818381 - 2³⁰ = 2542648076557 is a prime.

It is a super-2 number, since 2×2543721818381² (a number of 26 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2543721818881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1271860909190 + 1271860909191.

It is an arithmetic number, because the mean of its divisors is an integer number (1271860909191).

Almost surely, 2^{2543721818381} is an apocalyptic number.

It is an amenable number.

2543721818381 is a deficient number, since it is larger than the sum of its proper divisors (1).

2543721818381 is an equidigital number, since it uses as much as digits as its factorization.

2543721818381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2580480, while the sum is 53.

The spelling of 2543721818381 in words is "two trillion, five hundred forty-three billion, seven hundred twenty-one million, eight hundred eighteen thousand, three hundred eighty-one".