21115244 has 12 divisors (see below), whose sum is σ = 37188144. Its totient is φ = 10490064.

The previous prime is 21115231. The next prime is 21115249. The reversal of 21115244 is 44251112.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21115249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16184 + ... + 17439.

It is an arithmetic number, because the mean of its divisors is an integer number (3099012).

Almost surely, 2^21115244 is an apocalyptic number.

It is an amenable number.

21115244 is a deficient number, since it is larger than the sum of its proper divisors (16072900).

21115244 is a wasteful number, since it uses less digits than its factorization.

21115244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33784 (or 33782 counting only the distinct ones).

The product of its digits is 320, while the sum is 20.

The square root of 21115244 is about 4595.1326422640. The cubic root of 21115244 is about 276.3961789225.

Adding to 21115244 its reverse (44251112), we get a palindrome (65366356).

The spelling of 21115244 in words is "twenty-one million, one hundred fifteen thousand, two hundred forty-four".