21244736 has 28 divisors (see below), whose sum is σ = 44378880. Its totient is φ = 10062720.

The previous prime is 21244723. The next prime is 21244757. The reversal of 21244736 is 63744212.

It is a junction number, because it is equal to n+sod(n) for n = 21244699 and 21244708.

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, 7520 + ... + 9951.

It is an arithmetic number, because the mean of its divisors is an integer number (1584960).

Almost surely, 2^21244736 is an apocalyptic number.

It is an amenable number.

21244736 is an abundant number, since it is smaller than the sum of its proper divisors (23134144).

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

21244736 is a wasteful number, since it uses less digits than its factorization.

21244736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17502 (or 17492 counting only the distinct ones).

The product of its digits is 8064, while the sum is 29.

The square root of 21244736 is about 4609.2012323178. The cubic root of 21244736 is about 276.9600397638.

Adding to 21244736 its reverse (63744212), we get a palindrome (84988948).

The spelling of 21244736 in words is "twenty-one million, two hundred forty-four thousand, seven hundred thirty-six".