265561621664 has 48 divisors (see below), whose sum is σ = 550651399200. Its totient is φ = 125721517824.

The previous prime is 265561621639. The next prime is 265561621667. The reversal of 265561621664 is 466126165562.

It is not an unprimeable number, because it can be changed into a prime (265561621667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 965639 + ... + 1209785.

It is an arithmetic number, because the mean of its divisors is an integer number (11471904150).

Almost surely, 2^265561621664 is an apocalyptic number.

It is an amenable number.

265561621664 is an abundant number, since it is smaller than the sum of its proper divisors (285089777536).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

265561621664 is a wasteful number, since it uses less digits than its factorization.

265561621664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245965 (or 245957 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 50.

The spelling of 265561621664 in words is "two hundred sixty-five billion, five hundred sixty-one million, six hundred twenty-one thousand, six hundred sixty-four".