521538 has 8 divisors (see below), whose sum is σ = 1043088. Its totient is φ = 173844.

The previous prime is 521537. The next prime is 521539. The reversal of 521538 is 835125.

It is an interprime number because it is at equal distance from previous prime (521537) and next prime (521539).

It is a sphenic number, since it is the product of 3 distinct primes.

521538 is an admirable number.

It is a d-powerful number, because it can be written as 5² + 2¹⁸ + 5⁷ + 1 + 3¹¹ + 8⁴ .

It is not an unprimeable number, because it can be changed into a prime (521533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43456 + ... + 43467.

It is an arithmetic number, because the mean of its divisors is an integer number (130386).

2⁵²¹⁵³⁸ is an apocalyptic number.

521538 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521538 is a wasteful number, since it uses less digits than its factorization.

521538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86928.

The product of its digits is 1200, while the sum is 24.

The square root of 521538 is about 722.1758788550. The cubic root of 521538 is about 80.4937176019.

It can be divided in two parts, 5215 and 38, that added together give a triangular number (5253 = T₁₀₂).

The spelling of 521538 in words is "five hundred twenty-one thousand, five hundred thirty-eight".