523921 has 4 divisors (see below), whose sum is σ = 531172. Its totient is φ = 516672.

The previous prime is 523907. The next prime is 523927. The reversal of 523921 is 129325.

It is the 296-th star number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 408321 + 115600 = 639^2 + 340^2 .

It is a cyclic number.

It is not a de Polignac number, because 523921 - 2⁷ = 523793 is a prime.

It is a Duffinian number.

523921 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 523892 and 523901.

It is not an unprimeable number, because it can be changed into a prime (523927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3516 + ... + 3661.

It is an arithmetic number, because the mean of its divisors is an integer number (132793).

2⁵²³⁹²¹ is an apocalyptic number.

It is an amenable number.

523921 is a deficient number, since it is larger than the sum of its proper divisors (7251).

523921 is an equidigital number, since it uses as much as digits as its factorization.

523921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7250.

The product of its digits is 540, while the sum is 22.

The square root of 523921 is about 723.8238736046. The cubic root of 523921 is about 80.6161280625.

It can be divided in two parts, 523 and 921, that added together give a square (1444 = 38²).

The spelling of 523921 in words is "five hundred twenty-three thousand, nine hundred twenty-one".