21636336 has 40 divisors (see below), whose sum is σ = 56402640. Its totient is φ = 7146496.

The previous prime is 21636331. The next prime is 21636341. The reversal of 21636336 is 63363612.

It is an interprime number because it is at equal distance from previous prime (21636331) and next prime (21636341).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21636331) 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, 3430 + ... + 7418.

It is an arithmetic number, because the mean of its divisors is an integer number (1410066).

Almost surely, 2^21636336 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21636336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28201320).

21636336 is an abundant number, since it is smaller than the sum of its proper divisors (34766304).

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

21636336 is a wasteful number, since it uses less digits than its factorization.

21636336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4113 (or 4107 counting only the distinct ones).

The product of its digits is 11664, while the sum is 30.

The square root of 21636336 is about 4651.4875040142. The cubic root of 21636336 is about 278.6514062088.

Adding to 21636336 its reverse (63363612), we get a palindrome (84999948).

The spelling of 21636336 in words is "twenty-one million, six hundred thirty-six thousand, three hundred thirty-six".