4381521221 has 16 divisors (see below), whose sum is σ = 5464370688. Its totient is φ = 3413113200.

The previous prime is 4381521217. The next prime is 4381521233. The reversal of 4381521221 is 1221251834.

It is a happy number.

It is not a de Polignac number, because 4381521221 - 2² = 4381521217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4381521251) 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 15 ways as a sum of consecutive naturals, for example, 320006 + ... + 333416.

It is an arithmetic number, because the mean of its divisors is an integer number (341523168).

Almost surely, 2^4381521221 is an apocalyptic number.

It is an amenable number.

4381521221 is a deficient number, since it is larger than the sum of its proper divisors (1082849467).

4381521221 is a wasteful number, since it uses less digits than its factorization.

4381521221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17672.

The product of its digits is 3840, while the sum is 29.

The square root of 4381521221 is about 66193.0602178204. The cubic root of 4381521221 is about 1636.3453743894.

The spelling of 4381521221 in words is "four billion, three hundred eighty-one million, five hundred twenty-one thousand, two hundred twenty-one".