21793816 has 32 divisors (see below), whose sum is σ = 44815680. Its totient is φ = 9853600.

The previous prime is 21793799. The next prime is 21793829. The reversal of 21793816 is 61839712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19431 + ... + 20521.

It is an arithmetic number, because the mean of its divisors is an integer number (1400490).

Almost surely, 2^21793816 is an apocalyptic number.

It is an amenable number.

21793816 is an abundant number, since it is smaller than the sum of its proper divisors (23021864).

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

21793816 is a wasteful number, since it uses less digits than its factorization.

21793816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1335 (or 1331 counting only the distinct ones).

The product of its digits is 18144, while the sum is 37.

The square root of 21793816 is about 4668.3847313605. The cubic root of 21793816 is about 279.3258270353.

It can be divided in two parts, 2179 and 3816, that added together give a palindrome (5995).

The spelling of 21793816 in words is "twenty-one million, seven hundred ninety-three thousand, eight hundred sixteen".