263521 has 2 divisors, whose sum is σ = 263522. Its totient is φ = 263520.

The previous prime is 263519. The next prime is 263533. The reversal of 263521 is 125362.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 245025 + 18496 = 495^2 + 136^2 .

It is a cyclic number.

It is not a de Polignac number, because 263521 - 2¹ = 263519 is a prime.

Together with 263519, it forms a pair of twin primes.

It is a d-powerful number, because it can be written as 2⁴ + 6 + 5⁴ + 3⁶ + 2¹⁸ + 1 .

It is not a weakly prime, because it can be changed into another prime (263561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 131760 + 131761.

It is an arithmetic number, because the mean of its divisors is an integer number (131761).

2²⁶³⁵²¹ is an apocalyptic number.

It is an amenable number.

263521 is a deficient number, since it is larger than the sum of its proper divisors (1).

263521 is an equidigital number, since it uses as much as digits as its factorization.

263521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 360, while the sum is 19.

The square root of 263521 is about 513.3429652776. The cubic root of 263521 is about 64.1118649055. Note that the first 3 decimals are identical.

Adding to 263521 its reverse (125362), we get a palindrome (388883).

It can be divided in two parts, 263 and 521, that added together give a square (784 = 28²).

The spelling of 263521 in words is "two hundred sixty-three thousand, five hundred twenty-one".