521043521 has 4 divisors (see below), whose sum is σ = 521755092. Its totient is φ = 520331952.

The previous prime is 521043503. The next prime is 521043533. The reversal of 521043521 is 125340125.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 482417296 + 38626225 = 21964^2 + 6215^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521043521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521043571) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 354686 + ... + 356151.

It is an arithmetic number, because the mean of its divisors is an integer number (130438773).

Almost surely, 2^521043521 is an apocalyptic number.

It is an amenable number.

521043521 is a deficient number, since it is larger than the sum of its proper divisors (711571).

521043521 is an equidigital number, since it uses as much as digits as its factorization.

521043521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 711570.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 521043521 is about 22826.3777459324. The cubic root of 521043521 is about 804.6827040612.

Adding to 521043521 its reverse (125340125), we get a palindrome (646383646).

The spelling of 521043521 in words is "five hundred twenty-one million, forty-three thousand, five hundred twenty-one".