263640 has 64 divisors (see below), whose sum is σ = 856800. Its totient is φ = 64896.

The previous prime is 263621. The next prime is 263647. The reversal of 263640 is 46362.

263640 = T₂₇ + T₂₈ + ... + T₁₁₆.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (263647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20274 + ... + 20286.

263640 is a Friedman number, since it can be written as (60*26^3)/4, using all its digits and the basic arithmetic operations.

2²⁶³⁶⁴⁰ is an apocalyptic number.

263640 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 263640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (428400).

263640 is an abundant number, since it is smaller than the sum of its proper divisors (593160).

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

263640 is a wasteful number, since it uses less digits than its factorization.

263640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53 (or 23 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 263640 is about 513.4588591114. The cubic root of 263640 is about 64.1215139326.

It can be divided in two parts, 263 and 640, that added together give a triangular number (903 = T₄₂).

The spelling of 263640 in words is "two hundred sixty-three thousand, six hundred forty".