2543405621 has 2 divisors, whose sum is σ = 2543405622. Its totient is φ = 2543405620.

The previous prime is 2543405609. The next prime is 2543405639. The reversal of 2543405621 is 1265043452.

2543405621 is digitally balanced in base 2, 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., 1865376100 + 678029521 = 43190^2 + 26039^2 .

It is a cyclic number.

It is not a de Polignac number, because 2543405621 - 2¹⁰ = 2543404597 is a prime.

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 (2543405671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1271702810 + 1271702811.

It is an arithmetic number, because the mean of its divisors is an integer number (1271702811).

Almost surely, 2^2543405621 is an apocalyptic number.

It is an amenable number.

2543405621 is a deficient number, since it is larger than the sum of its proper divisors (1).

2543405621 is an equidigital number, since it uses as much as digits as its factorization.

2543405621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28800, while the sum is 32.

The square root of 2543405621 is about 50432.1883423672. The cubic root of 2543405621 is about 1365.0185153155.

The spelling of 2543405621 in words is "two billion, five hundred forty-three million, four hundred five thousand, six hundred twenty-one".