221521332 has 24 divisors (see below), whose sum is σ = 518756896. Its totient is φ = 73572768.

The previous prime is 221521301. The next prime is 221521409. The reversal of 221521332 is 233125122.

It is a junction number, because it is equal to n+sod(n) for n = 221521299 and 221521308.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 29998 + ... + 36645.

Almost surely, 2^221521332 is an apocalyptic number.

It is an amenable number.

221521332 is an abundant number, since it is smaller than the sum of its proper divisors (297235564).

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

221521332 is a wasteful number, since it uses less digits than its factorization.

221521332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66927 (or 66925 counting only the distinct ones).

The product of its digits is 720, while the sum is 21.

The square root of 221521332 is about 14883.5927114390. The cubic root of 221521332 is about 605.0693925823.

Adding to 221521332 its reverse (233125122), we get a palindrome (454646454).

The spelling of 221521332 in words is "two hundred twenty-one million, five hundred twenty-one thousand, three hundred thirty-two".