266509440 has 320 divisors, whose sum is σ = 979707960. Its totient is φ = 69009408.

The previous prime is 266509429. The next prime is 266509457. The reversal of 266509440 is 44905662.

It can be written as a sum of positive squares in 4 ways, for example, as 230796864 + 35712576 = 15192^2 + 5976^2 .

It is a tau number, because it is divible by the number of its divisors (320).

It is a super-2 number, since 2×266509440² = 142054563218227200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 266509395 and 266509404.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2747472 + ... + 2747568.

Almost surely, 2^266509440 is an apocalyptic number.

266509440 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 266509440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (489853980).

266509440 is an abundant number, since it is smaller than the sum of its proper divisors (713198520).

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

266509440 is an equidigital number, since it uses as much as digits as its factorization.

266509440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181 (or 160 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 266509440 is about 16325.1168449111. The cubic root of 266509440 is about 643.5330643027.

The spelling of 266509440 in words is "two hundred sixty-six million, five hundred nine thousand, four hundred forty".