16221644 has 12 divisors (see below), whose sum is σ = 28429464. Its totient is φ = 8098944.

The previous prime is 16221641. The next prime is 16221659. The reversal of 16221644 is 44612261.

It is not an unprimeable number, because it can be changed into a prime (16221641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 572 + ... + 5724.

It is an arithmetic number, because the mean of its divisors is an integer number (2369122).

Almost surely, 2^16221644 is an apocalyptic number.

It is an amenable number.

16221644 is a deficient number, since it is larger than the sum of its proper divisors (12207820).

16221644 is a wasteful number, since it uses less digits than its factorization.

16221644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5944 (or 5942 counting only the distinct ones).

The product of its digits is 2304, while the sum is 26.

The square root of 16221644 is about 4027.6102095411. The cubic root of 16221644 is about 253.1424362119.

The spelling of 16221644 in words is "sixteen million, two hundred twenty-one thousand, six hundred forty-four".