16221156 has 60 divisors (see below), whose sum is σ = 44233392. Its totient is φ = 4626384.

The previous prime is 16221151. The next prime is 16221197. The reversal of 16221156 is 65112261.

It is not an unprimeable number, because it can be changed into a prime (16221151) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 28531 + ... + 29093.

Almost surely, 2^16221156 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16221156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22116696).

16221156 is an abundant number, since it is smaller than the sum of its proper divisors (28012236).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16221156 is an equidigital number, since it uses as much as digits as its factorization.

16221156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 598 (or 575 counting only the distinct ones).

The product of its digits is 720, while the sum is 24.

The square root of 16221156 is about 4027.5496272548. The cubic root of 16221156 is about 253.1398977362.

The spelling of 16221156 in words is "sixteen million, two hundred twenty-one thousand, one hundred fifty-six".