16821312 has 56 divisors (see below), whose sum is σ = 45110400. Its totient is φ = 5531136.

The previous prime is 16821269. The next prime is 16821319. The reversal of 16821312 is 21312861.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (16821319) 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, 14614 + ... + 15722.

Almost surely, 2^16821312 is an apocalyptic number.

16821312 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16821312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22555200).

16821312 is an abundant number, since it is smaller than the sum of its proper divisors (28289088).

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

16821312 is a wasteful number, since it uses less digits than its factorization.

16821312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1203 (or 1193 counting only the distinct ones).

The product of its digits is 576, while the sum is 24.

The square root of 16821312 is about 4101.3792801934. The cubic root of 16821312 is about 256.2240876435.

The spelling of 16821312 in words is "sixteen million, eight hundred twenty-one thousand, three hundred twelve".