265605561 has 48 divisors (see below), whose sum is σ = 434056896. Its totient is φ = 161320896.

The previous prime is 265605553. The next prime is 265605623. The reversal of 265605561 is 165506562.

It is a happy number.

It is not a de Polignac number, because 265605561 - 2³ = 265605553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (265605511) 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 in 47 ways as a sum of consecutive naturals, for example, 261691 + ... + 262703.

It is an arithmetic number, because the mean of its divisors is an integer number (9042852).

Almost surely, 2^265605561 is an apocalyptic number.

It is an amenable number.

265605561 is a deficient number, since it is larger than the sum of its proper divisors (168451335).

265605561 is a wasteful number, since it uses less digits than its factorization.

265605561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1124 (or 1112 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The square root of 265605561 is about 16297.4096407987. The cubic root of 265605561 is about 642.8047162960.

The spelling of 265605561 in words is "two hundred sixty-five million, six hundred five thousand, five hundred sixty-one".