2561905169 has 2 divisors, whose sum is σ = 2561905170. Its totient is φ = 2561905168.

The previous prime is 2561905111. The next prime is 2561905183. The reversal of 2561905169 is 9615091652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2561574544 + 330625 = 50612^2 + 575^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561905169 - 2¹² = 2561901073 is a prime.

It is a super-2 number, since 2×2561905169² = 13126716189897837122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2561905189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280952584 + 1280952585.

It is an arithmetic number, because the mean of its divisors is an integer number (1280952585).

Almost surely, 2^2561905169 is an apocalyptic number.

It is an amenable number.

2561905169 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561905169 is an equidigital number, since it uses as much as digits as its factorization.

2561905169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145800, while the sum is 44.

The square root of 2561905169 is about 50615.2661654564. The cubic root of 2561905169 is about 1368.3200266477.

The spelling of 2561905169 in words is "two billion, five hundred sixty-one million, nine hundred five thousand, one hundred sixty-nine".