521766 has 48 divisors (see below), whose sum is σ = 1336608. Its totient is φ = 144000.

The previous prime is 521753. The next prime is 521767. The reversal of 521766 is 667125.

It is a nialpdrome in base 14.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 521766.

It is not an unprimeable number, because it can be changed into a prime (521767) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5116 + ... + 5216.

It is an arithmetic number, because the mean of its divisors is an integer number (27846).

2⁵²¹⁷⁶⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 521766, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (668304).

521766 is an abundant number, since it is smaller than the sum of its proper divisors (814842).

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

521766 is a wasteful number, since it uses less digits than its factorization.

521766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 154 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 521766 is about 722.3337178895. Note that the first 3 decimals coincide. The cubic root of 521766 is about 80.5054456663.

The spelling of 521766 in words is "five hundred twenty-one thousand, seven hundred sixty-six".