521641 has 2 divisors, whose sum is σ = 521642. Its totient is φ = 521640.

The previous prime is 521603. The next prime is 521657. The reversal of 521641 is 146125.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 275625 + 246016 = 525^2 + 496^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521641 is a prime.

It is not a weakly prime, because it can be changed into another prime (521671) 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 as a sum of consecutive naturals, namely, 260820 + 260821.

It is an arithmetic number, because the mean of its divisors is an integer number (260821).

2⁵²¹⁶⁴¹ is an apocalyptic number.

It is an amenable number.

521641 is a deficient number, since it is larger than the sum of its proper divisors (1).

521641 is an equidigital number, since it uses as much as digits as its factorization.

521641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 240, while the sum is 19.

The square root of 521641 is about 722.2471876027. The cubic root of 521641 is about 80.4990162296.

Adding to 521641 its reverse (146125), we get a palindrome (667766).

The spelling of 521641 in words is "five hundred twenty-one thousand, six hundred forty-one".