521761 has 4 divisors (see below), whose sum is σ = 538624. Its totient is φ = 504900.

The previous prime is 521753. The next prime is 521767. The reversal of 521761 is 167125.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 521761 - 2³ = 521753 is a prime.

It is a super-2 number, since 2×521761² = 544469082242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521767) 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, 8385 + ... + 8446.

It is an arithmetic number, because the mean of its divisors is an integer number (134656).

2⁵²¹⁷⁶¹ is an apocalyptic number.

It is an amenable number.

521761 is a deficient number, since it is larger than the sum of its proper divisors (16863).

521761 is a wasteful number, since it uses less digits than its factorization.

521761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16862.

The product of its digits is 420, while the sum is 22.

The square root of 521761 is about 722.3302568770. The cubic root of 521761 is about 80.5051885086.

Adding to 521761 its reverse (167125), we get a palindrome (688886).

The spelling of 521761 in words is "five hundred twenty-one thousand, seven hundred sixty-one".