263865 has 24 divisors (see below), whose sum is σ = 492480. Its totient is φ = 120288.

The previous prime is 263863. The next prime is 263867. The reversal of 263865 is 568362.

It is an interprime number because it is at equal distance from previous prime (263863) and next prime (263867).

It is not a de Polignac number, because 263865 - 2¹ = 263863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (263863) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 556 + ... + 914.

It is an arithmetic number, because the mean of its divisors is an integer number (20520).

2²⁶³⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

263865 is a deficient number, since it is larger than the sum of its proper divisors (228615).

263865 is a wasteful number, since it uses less digits than its factorization.

263865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381 (or 374 counting only the distinct ones).

The product of its digits is 8640, while the sum is 30.

The square root of 263865 is about 513.6779146508. The cubic root of 263865 is about 64.1397499594.

It can be divided in two parts, 263 and 865, that added together give a triangular number (1128 = T₄₇).

The spelling of 263865 in words is "two hundred sixty-three thousand, eight hundred sixty-five".