21038816 has 24 divisors (see below), whose sum is σ = 41731200. Its totient is φ = 10440448.

The previous prime is 21038803. The next prime is 21038821. The reversal of 21038816 is 61883012.

It is a congruent number.

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, 1985 + ... + 6783.

It is an arithmetic number, because the mean of its divisors is an integer number (1738800).

Almost surely, 2^21038816 is an apocalyptic number.

It is an amenable number.

21038816 is a deficient number, since it is larger than the sum of its proper divisors (20692384).

21038816 is a wasteful number, since it uses less digits than its factorization.

21038816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4946 (or 4938 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21038816 is about 4586.8089125230. The cubic root of 21038816 is about 276.0622977766.

The spelling of 21038816 in words is "twenty-one million, thirty-eight thousand, eight hundred sixteen".