21196816 has 15 divisors (see below), whose sum is σ = 41104543. Its totient is φ = 10589200.

The previous prime is 21196811. The next prime is 21196817. The reversal of 21196816 is 61869112.

The square root of 21196816 is 4604.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21196811) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 17841 + ... + 18991.

Almost surely, 2^21196816 is an apocalyptic number.

21196816 is the 4604-th square number.

It is an amenable number.

21196816 is a deficient number, since it is larger than the sum of its proper divisors (19907727).

21196816 is an frugal number, since it uses more digits than its factorization.

21196816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2310 (or 1153 counting only the distinct ones).

The product of its digits is 5184, while the sum is 34.

The cubic root of 21196816 is about 276.7516443535.

Multiplying 21196816 by its product of digits (5184), we get a square (109884294144 = 331488²).

The spelling of 21196816 in words is "twenty-one million, one hundred ninety-six thousand, eight hundred sixteen".