521421 has 4 divisors (see below), whose sum is σ = 695232. Its totient is φ = 347612.

The previous prime is 521401. The next prime is 521429. The reversal of 521421 is 124125.

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 521421 - 2⁶ = 521357 is a prime.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 521421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86901 + ... + 86906.

It is an arithmetic number, because the mean of its divisors is an integer number (173808).

2⁵²¹⁴²¹ is an apocalyptic number.

It is an amenable number.

521421 is a deficient number, since it is larger than the sum of its proper divisors (173811).

521421 is a wasteful number, since it uses less digits than its factorization.

521421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173810.

The product of its digits is 80, while the sum is 15.

The square root of 521421 is about 722.0948691135. The cubic root of 521421 is about 80.4876979259.

Adding to 521421 its reverse (124125), we get a palindrome (645546).

The spelling of 521421 in words is "five hundred twenty-one thousand, four hundred twenty-one".