521806 has 8 divisors (see below), whose sum is σ = 788760. Its totient is φ = 258888.

The previous prime is 521791. The next prime is 521809. The reversal of 521806 is 608125.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521809) 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, 661 + ... + 1216.

It is an arithmetic number, because the mean of its divisors is an integer number (98595).

2⁵²¹⁸⁰⁶ is an apocalyptic number.

521806 is a deficient number, since it is larger than the sum of its proper divisors (266954).

521806 is a wasteful number, since it uses less digits than its factorization.

521806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2018.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 521806 is about 722.3614053921. The cubic root of 521806 is about 80.5075028692.

The spelling of 521806 in words is "five hundred twenty-one thousand, eight hundred six".