21108416 has 84 divisors (see below), whose sum is σ = 50035968. Its totient is φ = 8805888.

The previous prime is 21108413. The next prime is 21108419. The reversal of 21108416 is 61480112.

It is an interprime number because it is at equal distance from previous prime (21108413) and next prime (21108419).

It is a junction number, because it is equal to n+sod(n) for n = 21108391 and 21108400.

It is not an unprimeable number, because it can be changed into a prime (21108413) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 166145 + ... + 166271.

Almost surely, 2^21108416 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 21108416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25017984).

21108416 is an abundant number, since it is smaller than the sum of its proper divisors (28927552).

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

21108416 is a wasteful number, since it uses less digits than its factorization.

21108416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 21108416 is about 4594.3896221370. The cubic root of 21108416 is about 276.3663831256.

Adding to 21108416 its reverse (61480112), we get a palindrome (82588528).

The spelling of 21108416 in words is "twenty-one million, one hundred eight thousand, four hundred sixteen".