521506 has 4 divisors (see below), whose sum is σ = 782262. Its totient is φ = 260752.

The previous prime is 521503. The next prime is 521519. The reversal of 521506 is 605125.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 349281 + 172225 = 591^2 + 415^2 .

It is a nialpdrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521503) 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 as a sum of consecutive naturals, namely, 130375 + ... + 130378.

2⁵²¹⁵⁰⁶ is an apocalyptic number.

521506 is a deficient number, since it is larger than the sum of its proper divisors (260756).

521506 is a wasteful number, since it uses less digits than its factorization.

521506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260755.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 521506 is about 722.1537232473. The cubic root of 521506 is about 80.4920712842.

The spelling of 521506 in words is "five hundred twenty-one thousand, five hundred six".