21916044 has 54 divisors (see below), whose sum is σ = 58642220. Its totient is φ = 6882192.

The previous prime is 21916021. The next prime is 21916051. The reversal of 21916044 is 44061912.

It is a junction number, because it is equal to n+sod(n) for n = 21915999 and 21916017.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 122347 + ... + 122525.

Almost surely, 2^21916044 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 21916044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29321110).

21916044 is an abundant number, since it is smaller than the sum of its proper divisors (36726176).

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

21916044 is a wasteful number, since it uses less digits than its factorization.

21916044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 387 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21916044 is about 4681.4574653627. The cubic root of 21916044 is about 279.8470423082.

Adding to 21916044 its reverse (44061912), we get a palindrome (65977956).

The spelling of 21916044 in words is "twenty-one million, nine hundred sixteen thousand, forty-four".