521521002 has 48 divisors (see below), whose sum is σ = 1199350152. Its totient is φ = 163215360.

The previous prime is 521520971. The next prime is 521521003. The reversal of 521521002 is 200125125.

It can be written as a sum of positive squares in 4 ways, for example, as 365995161 + 155525841 = 19131^2 + 12471^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

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 23 ways as a sum of consecutive naturals, for example, 139218 + ... + 142914.

Almost surely, 2^521521002 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 521521002, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (599675076).

521521002 is an abundant number, since it is smaller than the sum of its proper divisors (677829150).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521521002 is a wasteful number, since it uses less digits than its factorization.

521521002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4183 (or 4180 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 521521002 is about 22836.8343252737. The cubic root of 521521002 is about 804.9284310690.

Adding to 521521002 its reverse (200125125), we get a palindrome (721646127).

The spelling of 521521002 in words is "five hundred twenty-one million, five hundred twenty-one thousand, two".