21221506016 has 12 divisors (see below), whose sum is σ = 41779840032. Its totient is φ = 10610752992.

The previous prime is 21221506013. The next prime is 21221506039. The reversal of 21221506016 is 61060512212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221506013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331586000 + ... + 331586063.

It is an arithmetic number, because the mean of its divisors is an integer number (3481653336).

Almost surely, 2^21221506016 is an apocalyptic number.

It is an amenable number.

21221506016 is a deficient number, since it is larger than the sum of its proper divisors (20558334016).

21221506016 is an equidigital number, since it uses as much as digits as its factorization.

21221506016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663172073 (or 663172065 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 26.

The spelling of 21221506016 in words is "twenty-one billion, two hundred twenty-one million, five hundred six thousand, sixteen".