521523521 has 4 divisors (see below), whose sum is σ = 521623344. Its totient is φ = 521423700.

The previous prime is 521523503. The next prime is 521523539. The reversal of 521523521 is 125325125.

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 an interprime number because it is at equal distance from previous prime (521523503) and next prime (521523539).

It is a cyclic number.

It is not a de Polignac number, because 521523521 - 2¹⁰ = 521522497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521523581) 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, 41615 + ... + 52676.

It is an arithmetic number, because the mean of its divisors is an integer number (130405836).

Almost surely, 2^521523521 is an apocalyptic number.

It is an amenable number.

521523521 is a deficient number, since it is larger than the sum of its proper divisors (99823).

521523521 is an equidigital number, since it uses as much as digits as its factorization.

521523521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99822.

The product of its digits is 3000, while the sum is 26.

The square root of 521523521 is about 22836.8894773347. The cubic root of 521523521 is about 804.9297270292.

Adding to 521523521 its reverse (125325125), we get a palindrome (646848646).

The spelling of 521523521 in words is "five hundred twenty-one million, five hundred twenty-three thousand, five hundred twenty-one".