521557 has 2 divisors, whose sum is σ = 521558. Its totient is φ = 521556.

The previous prime is 521551. The next prime is 521567. The reversal of 521557 is 755125.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 461041 + 60516 = 679^2 + 246^2 .

It is a cyclic number.

It is not a de Polignac number, because 521557 - 2⁷ = 521429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521551) 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, 260778 + 260779.

It is an arithmetic number, because the mean of its divisors is an integer number (260779).

2⁵²¹⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

521557 is a deficient number, since it is larger than the sum of its proper divisors (1).

521557 is an equidigital number, since it uses as much as digits as its factorization.

521557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1750, while the sum is 25.

The square root of 521557 is about 722.1890334255. The cubic root of 521557 is about 80.4946950711.

It can be divided in two parts, 52155 and 7, that multiplied together give a triangular number (365085 = T₈₅₄).

The spelling of 521557 in words is "five hundred twenty-one thousand, five hundred fifty-seven".