21016844 has 12 divisors (see below), whose sum is σ = 37245600. Its totient is φ = 10375248.

The previous prime is 21016837. The next prime is 21016859. The reversal of 21016844 is 44861012.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32939 + ... + 33570.

It is an arithmetic number, because the mean of its divisors is an integer number (3103800).

Almost surely, 2^21016844 is an apocalyptic number.

It is an amenable number.

21016844 is a deficient number, since it is larger than the sum of its proper divisors (16228756).

21016844 is a wasteful number, since it uses less digits than its factorization.

21016844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66592 (or 66590 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 21016844 is about 4584.4131576462. The cubic root of 21016844 is about 275.9661619231.

Adding to 21016844 its reverse (44861012), we get a palindrome (65877856).

The spelling of 21016844 in words is "twenty-one million, sixteen thousand, eight hundred forty-four".