265665840 has 160 divisors (see below), whose sum is σ = 908084736. Its totient is φ = 63713280.

The previous prime is 265665821. The next prime is 265665857. The reversal of 265665840 is 48566562.

It is a junction number, because it is equal to n+sod(n) for n = 265665792 and 265665801.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 271432 + ... + 272408.

Almost surely, 2^265665840 is an apocalyptic number.

265665840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 265665840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (454042368).

265665840 is an abundant number, since it is smaller than the sum of its proper divisors (642418896).

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

265665840 is a wasteful number, since it uses less digits than its factorization.

265665840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1107 (or 1101 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 42.

The square root of 265665840 is about 16299.2588788570. The cubic root of 265665840 is about 642.8533406477.

The spelling of 265665840 in words is "two hundred sixty-five million, six hundred sixty-five thousand, eight hundred forty".