21146216 has 64 divisors (see below), whose sum is σ = 50426880. Its totient is φ = 8087040.

The previous prime is 21146207. The next prime is 21146231. The reversal of 21146216 is 61264112.

It is a super-3 number, since 3×21146216³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 21146191 and 21146200.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22100 + ... + 23036.

It is an arithmetic number, because the mean of its divisors is an integer number (787920).

Almost surely, 2^21146216 is an apocalyptic number.

21146216 is a gapful number since it is divisible by the number (26) 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 21146216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25213440).

21146216 is an abundant number, since it is smaller than the sum of its proper divisors (29280664).

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

21146216 is a wasteful number, since it uses less digits than its factorization.

21146216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994 (or 990 counting only the distinct ones).

The product of its digits is 576, while the sum is 23.

The square root of 21146216 is about 4598.5014950525. The cubic root of 21146216 is about 276.5312529052.

The spelling of 21146216 in words is "twenty-one million, one hundred forty-six thousand, two hundred sixteen".