21241216 has 16 divisors (see below), whose sum is σ = 42316740. Its totient is φ = 10620544.

The previous prime is 21241163. The next prime is 21241217. The reversal of 21241216 is 61214212.

It is a tau number, because it is divible by the number of its divisors (16).

It is a junction number, because it is equal to n+sod(n) for n = 21241193 and 21241202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21241217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82846 + ... + 83101.

Almost surely, 2^21241216 is an apocalyptic number.

It is an amenable number.

21241216 is a deficient number, since it is larger than the sum of its proper divisors (21075524).

21241216 is an equidigital number, since it uses as much as digits as its factorization.

21241216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165961 (or 165949 counting only the distinct ones).

The product of its digits is 192, while the sum is 19.

The square root of 21241216 is about 4608.8193715962. The cubic root of 21241216 is about 276.9447425911.

Adding to 21241216 its reverse (61214212), we get a palindrome (82455428).

The spelling of 21241216 in words is "twenty-one million, two hundred forty-one thousand, two hundred sixteen".