521521001 has 4 divisors (see below), whose sum is σ = 530360400. Its totient is φ = 512681604.

The previous prime is 521520971. The next prime is 521521003. The reversal of 521521001 is 100125125.

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 521521001 - 2²⁶ = 454412137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521521003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4419611 + ... + 4419728.

It is an arithmetic number, because the mean of its divisors is an integer number (132590100).

Almost surely, 2^521521001 is an apocalyptic number.

It is an amenable number.

521521001 is a deficient number, since it is larger than the sum of its proper divisors (8839399).

521521001 is an equidigital number, since it uses as much as digits as its factorization.

521521001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8839398.

The product of its (nonzero) digits is 100, while the sum is 17.

The square root of 521521001 is about 22836.8343033793. The cubic root of 521521001 is about 804.9284305545.

Adding to 521521001 its reverse (100125125), we get a palindrome (621646126).

The spelling of 521521001 in words is "five hundred twenty-one million, five hundred twenty-one thousand, one".