2561999879 has 2 divisors, whose sum is σ = 2561999880. Its totient is φ = 2561999878.

The previous prime is 2561999863. The next prime is 2561999887. The reversal of 2561999879 is 9789991652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2561999879 - 2⁴ = 2561999863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2561999819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280999939 + 1280999940.

It is an arithmetic number, because the mean of its divisors is an integer number (1280999940).

Almost surely, 2^2561999879 is an apocalyptic number.

2561999879 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561999879 is an equidigital number, since it uses as much as digits as its factorization.

2561999879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22044960, while the sum is 65.

The square root of 2561999879 is about 50616.2017441056. The cubic root of 2561999879 is about 1368.3368880568.

The spelling of 2561999879 in words is "two billion, five hundred sixty-one million, nine hundred ninety-nine thousand, eight hundred seventy-nine".