521343621 has 30 divisors (see below), whose sum is σ = 789189830. Its totient is φ = 344373768.

The previous prime is 521343611. The next prime is 521343649. The reversal of 521343621 is 126343125.

521343621 is a `hidden beast` number, since 5 + 2 + 1 + 34 + 3 + 621 = 666.

It can be written as a sum of positive squares in only one way, i.e., 478296900 + 43046721 = 21870^2 + 6561^2 .

It is not a de Polignac number, because 521343621 - 2¹⁰ = 521342597 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521343611) 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 29 ways as a sum of consecutive naturals, for example, 4782915 + ... + 4783023.

Almost surely, 2^521343621 is an apocalyptic number.

It is an amenable number.

521343621 is a deficient number, since it is larger than the sum of its proper divisors (267846209).

521343621 is an frugal number, since it uses more digits than its factorization.

521343621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151 (or 112 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 521343621 is about 22832.9503349874. The cubic root of 521343621 is about 804.8371626445.

Adding to 521343621 its reverse (126343125), we get a palindrome (647686746).

It can be divided in two parts, 52134 and 3621, that added together give a palindrome (55755).

The spelling of 521343621 in words is "five hundred twenty-one million, three hundred forty-three thousand, six hundred twenty-one".