263391 has 4 divisors (see below), whose sum is σ = 351192. Its totient is φ = 175592.

The previous prime is 263387. The next prime is 263399. The reversal of 263391 is 193362.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 263391 - 2² = 263387 is a prime.

It is a D-number.

263391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (263399) 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, 43896 + ... + 43901.

It is an arithmetic number, because the mean of its divisors is an integer number (87798).

2²⁶³³⁹¹ is an apocalyptic number.

263391 is a deficient number, since it is larger than the sum of its proper divisors (87801).

263391 is an equidigital number, since it uses as much as digits as its factorization.

263391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87800.

The product of its digits is 972, while the sum is 24.

The square root of 263391 is about 513.2163286568. The cubic root of 263391 is about 64.1013206309.

The spelling of 263391 in words is "two hundred sixty-three thousand, three hundred ninety-one".