16224120721 has 4 divisors (see below), whose sum is σ = 16228936944. Its totient is φ = 16219304500.

The previous prime is 16224120709. The next prime is 16224120749. The reversal of 16224120721 is 12702142261.

16224120721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 16224120721 - 2²¹ = 16222023569 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16224120721.

It is not an unprimeable number, because it can be changed into a prime (16224120421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2403055 + ... + 2409796.

It is an arithmetic number, because the mean of its divisors is an integer number (4057234236).

Almost surely, 2^16224120721 is an apocalyptic number.

It is an amenable number.

16224120721 is a deficient number, since it is larger than the sum of its proper divisors (4816223).

16224120721 is an equidigital number, since it uses as much as digits as its factorization.

16224120721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4816222.

The product of its (nonzero) digits is 2688, while the sum is 28.

Adding to 16224120721 its reverse (12702142261), we get a palindrome (28926262982).

The spelling of 16224120721 in words is "sixteen billion, two hundred twenty-four million, one hundred twenty thousand, seven hundred twenty-one".