265646561 has 8 divisors (see below), whose sum is σ = 273350880. Its totient is φ = 258011712.

The previous prime is 265646531. The next prime is 265646567. The reversal of 265646561 is 165646562.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 265646561 - 2¹⁸ = 265384417 is a prime.

It is a super-2 number, since 2×265646561² = 141136190742253442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (265646567) 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 7 ways as a sum of consecutive naturals, for example, 9560 + ... + 24953.

It is an arithmetic number, because the mean of its divisors is an integer number (34168860).

Almost surely, 2^265646561 is an apocalyptic number.

It is an amenable number.

265646561 is a deficient number, since it is larger than the sum of its proper divisors (7704319).

265646561 is a wasteful number, since it uses less digits than its factorization.

265646561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34735.

The product of its digits is 259200, while the sum is 41.

The square root of 265646561 is about 16298.6674608693. The cubic root of 265646561 is about 642.8377899477.

Subtracting from 265646561 its reverse (165646562), we obtain a palindrome (99999999).

The spelling of 265646561 in words is "two hundred sixty-five million, six hundred forty-six thousand, five hundred sixty-one".