265001561 has 16 divisors (see below), whose sum is σ = 308689920. Its totient is φ = 225067920.

The previous prime is 265001543. The next prime is 265001567. The reversal of 265001561 is 165100562.

It is not a de Polignac number, because 265001561 - 2⁶ = 265001497 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 265001561.

It is not an unprimeable number, because it can be changed into a prime (265001567) 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 15 ways as a sum of consecutive naturals, for example, 1301 + ... + 23058.

It is an arithmetic number, because the mean of its divisors is an integer number (19293120).

Almost surely, 2^265001561 is an apocalyptic number.

It is an amenable number.

265001561 is a deficient number, since it is larger than the sum of its proper divisors (43688359).

265001561 is a wasteful number, since it uses less digits than its factorization.

265001561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24436.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 265001561 is about 16278.8685417630. The cubic root of 265001561 is about 642.3170900550.

Subtracting from 265001561 its reverse (165100562), we obtain a palindrome (99900999).

It can be divided in two parts, 265001 and 561, that added together give a palindrome (265562).

The spelling of 265001561 in words is "two hundred sixty-five million, one thousand, five hundred sixty-one".