21317244 has 24 divisors (see below), whose sum is σ = 53566800. Its totient is φ = 6559104.

The previous prime is 21317213. The next prime is 21317249. The reversal of 21317244 is 44271312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21317249) 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, 68169 + ... + 68480.

It is an arithmetic number, because the mean of its divisors is an integer number (2231950).

Almost surely, 2^21317244 is an apocalyptic number.

It is an amenable number.

21317244 is an abundant number, since it is smaller than the sum of its proper divisors (32249556).

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

21317244 is a wasteful number, since it uses less digits than its factorization.

21317244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136669 (or 136667 counting only the distinct ones).

The product of its digits is 1344, while the sum is 24.

The square root of 21317244 is about 4617.0601035724. The cubic root of 21317244 is about 277.2747689506.

Adding to 21317244 its reverse (44271312), we get a palindrome (65588556).

The spelling of 21317244 in words is "twenty-one million, three hundred seventeen thousand, two hundred forty-four".