16221312 has 48 divisors (see below), whose sum is σ = 46681830. Its totient is φ = 5406720.

The previous prime is 16221311. The next prime is 16221313. The reversal of 16221312 is 21312261.

It is an interprime number because it is at equal distance from previous prime (16221311) and next prime (16221313).

It can be written as a sum of positive squares in only one way, i.e., 11451456 + 4769856 = 3384^2 + 2184^2 .

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is not an unprimeable number, because it can be changed into a prime (16221311) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5889 + ... + 8192.

Almost surely, 2^16221312 is an apocalyptic number.

16221312 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

16221312 is an abundant number, since it is smaller than the sum of its proper divisors (30460518).

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

16221312 is a wasteful number, since it uses less digits than its factorization.

16221312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14101 (or 14086 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 16221312 is about 4027.5689938225. The cubic root of 16221312 is about 253.1407092217.

Adding to 16221312 its reverse (21312261), we get a palindrome (37533573).

The spelling of 16221312 in words is "sixteen million, two hundred twenty-one thousand, three hundred twelve".