263861 has 4 divisors (see below), whose sum is σ = 284172. Its totient is φ = 243552.

The previous prime is 263849. The next prime is 263863. The reversal of 263861 is 168362.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 168362 = 2 ⋅84181.

It can be written as a sum of positive squares in 2 ways, for example, as 78961 + 184900 = 281^2 + 430^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-263861 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 263861.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 10136 + ... + 10161.

It is an arithmetic number, because the mean of its divisors is an integer number (71043).

2²⁶³⁸⁶¹ is an apocalyptic number.

It is an amenable number.

263861 is a deficient number, since it is larger than the sum of its proper divisors (20311).

263861 is a wasteful number, since it uses less digits than its factorization.

263861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20310.

The product of its digits is 1728, while the sum is 26.

The square root of 263861 is about 513.6740211457. The cubic root of 263861 is about 64.1394258539.

The spelling of 263861 in words is "two hundred sixty-three thousand, eight hundred sixty-one".