521202421 has 4 divisors (see below), whose sum is σ = 527800000. Its totient is φ = 514604844.

The previous prime is 521202403. The next prime is 521202427. The reversal of 521202421 is 124202125.

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 521202421 - 2⁹ = 521201909 is a prime.

It is a super-2 number, since 2×521202421² = 543303927312522482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521202427) 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, 3298671 + ... + 3298828.

It is an arithmetic number, because the mean of its divisors is an integer number (131950000).

Almost surely, 2^521202421 is an apocalyptic number.

It is an amenable number.

521202421 is a deficient number, since it is larger than the sum of its proper divisors (6597579).

521202421 is an equidigital number, since it uses as much as digits as its factorization.

521202421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6597578.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 521202421 is about 22829.8581029318. The cubic root of 521202421 is about 804.7644957482.

Adding to 521202421 its reverse (124202125), we get a palindrome (645404546).

The spelling of 521202421 in words is "five hundred twenty-one million, two hundred two thousand, four hundred twenty-one".