521533221 has 8 divisors (see below), whose sum is σ = 758593824. Its totient is φ = 316080720.

The previous prime is 521533213. The next prime is 521533231. The reversal of 521533221 is 122335125.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 521533221 - 2³ = 521533213 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 521533191 and 521533200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521533231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7901986 + ... + 7902051.

It is an arithmetic number, because the mean of its divisors is an integer number (94824228).

Almost surely, 2^521533221 is an apocalyptic number.

It is an amenable number.

521533221 is a deficient number, since it is larger than the sum of its proper divisors (237060603).

521533221 is a wasteful number, since it uses less digits than its factorization.

521533221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15804051.

The product of its digits is 1800, while the sum is 24.

The square root of 521533221 is about 22837.1018520302. The cubic root of 521533221 is about 804.9347173890.

Adding to 521533221 its reverse (122335125), we get a palindrome (643868346).

The spelling of 521533221 in words is "five hundred twenty-one million, five hundred thirty-three thousand, two hundred twenty-one".