2561905111 has 2 divisors, whose sum is σ = 2561905112. Its totient is φ = 2561905110.

The previous prime is 2561905091. The next prime is 2561905169. The reversal of 2561905111 is 1115091652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2561905111 - 2¹³ = 2561896919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2561905811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280952555 + 1280952556.

It is an arithmetic number, because the mean of its divisors is an integer number (1280952556).

Almost surely, 2^2561905111 is an apocalyptic number.

2561905111 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561905111 is an equidigital number, since it uses as much as digits as its factorization.

2561905111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2700, while the sum is 31.

The square root of 2561905111 is about 50615.2655925068. The cubic root of 2561905111 is about 1368.3200163218.

Adding to 2561905111 its reverse (1115091652), we get a palindrome (3676996763).

The spelling of 2561905111 in words is "two billion, five hundred sixty-one million, nine hundred five thousand, one hundred eleven".