2561943871 has 2 divisors, whose sum is σ = 2561943872. Its totient is φ = 2561943870.

The previous prime is 2561943799. The next prime is 2561943947. The reversal of 2561943871 is 1783491652.

2561943871 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 is a cyclic number.

It is not a de Polignac number, because 2561943871 - 2¹³ = 2561935679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2561943271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280971935 + 1280971936.

It is an arithmetic number, because the mean of its divisors is an integer number (1280971936).

Almost surely, 2^2561943871 is an apocalyptic number.

2561943871 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561943871 is an equidigital number, since it uses as much as digits as its factorization.

2561943871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 46.

The square root of 2561943871 is about 50615.6484794969. The cubic root of 2561943871 is about 1368.3269168917.

The spelling of 2561943871 in words is "two billion, five hundred sixty-one million, nine hundred forty-three thousand, eight hundred seventy-one".