266240 has 52 divisors (see below), whose sum is σ = 688044. Its totient is φ = 98304.

The previous prime is 266239. The next prime is 266261. The reversal of 266240 is 42662.

It can be written as a sum of positive squares in 2 ways, for example, as 65536 + 200704 = 256^2 + 448^2 .

It is a tau number, because it is divible by the number of its divisors (52).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a nialpdrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (2) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20474 + ... + 20486.

266240 is a Friedman number, since it can be written as 4^6*(2^6+2^0), using all its digits and the basic arithmetic operations.

2²⁶⁶²⁴⁰ is an apocalyptic number.

266240 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 266240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (344022).

266240 is an abundant number, since it is smaller than the sum of its proper divisors (421804).

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

266240 is an equidigital number, since it uses as much as digits as its factorization.

266240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42 (or 20 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 266240 is about 515.9844958911. The cubic root of 266240 is about 64.3316121374.

The spelling of 266240 in words is "two hundred sixty-six thousand, two hundred forty".