21818836 has 24 divisors (see below), whose sum is σ = 41446944. Its totient is φ = 9990240.

The previous prime is 21818833. The next prime is 21818851. The reversal of 21818836 is 63881812.

It is a junction number, because it is equal to n+sod(n) for n = 21818795 and 21818804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21818833) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5211 + ... + 8413.

It is an arithmetic number, because the mean of its divisors is an integer number (1726956).

Almost surely, 2^21818836 is an apocalyptic number.

21818836 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21818836 is a deficient number, since it is larger than the sum of its proper divisors (19628108).

21818836 is a wasteful number, since it uses less digits than its factorization.

21818836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3351 (or 3349 counting only the distinct ones).

The product of its digits is 18432, while the sum is 37.

The square root of 21818836 is about 4671.0636904243. The cubic root of 21818836 is about 279.4326778268.

The spelling of 21818836 in words is "twenty-one million, eight hundred eighteen thousand, eight hundred thirty-six".