16221021 has 8 divisors (see below), whose sum is σ = 22036320. Its totient is φ = 10609872.

The previous prime is 16221017. The next prime is 16221031. The reversal of 16221021 is 12012261.

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

It is not a de Polignac number, because 16221021 - 2² = 16221017 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16221031) 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, 50851 + ... + 51168.

It is an arithmetic number, because the mean of its divisors is an integer number (2754540).

Almost surely, 2^16221021 is an apocalyptic number.

It is an amenable number.

16221021 is a deficient number, since it is larger than the sum of its proper divisors (5815299).

16221021 is a wasteful number, since it uses less digits than its factorization.

16221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102075.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 16221021 is about 4027.5328676499. The cubic root of 16221021 is about 253.1391954849.

Adding to 16221021 its reverse (12012261), we get a palindrome (28233282).

The spelling of 16221021 in words is "sixteen million, two hundred twenty-one thousand, twenty-one".