21311344 has 10 divisors (see below), whose sum is σ = 41290760. Its totient is φ = 10655664.

The previous prime is 21311261. The next prime is 21311347. The reversal of 21311344 is 44311312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665964 + ... + 665995.

It is an arithmetic number, because the mean of its divisors is an integer number (4129076).

Almost surely, 2^21311344 is an apocalyptic number.

It is an amenable number.

21311344 is a deficient number, since it is larger than the sum of its proper divisors (19979416).

21311344 is a wasteful number, since it uses less digits than its factorization.

21311344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1331967 (or 1331961 counting only the distinct ones).

The product of its digits is 288, while the sum is 19.

The square root of 21311344 is about 4616.4211246376. The cubic root of 21311344 is about 277.2491860300.

Adding to 21311344 its reverse (44311312), we get a palindrome (65622656).

The spelling of 21311344 in words is "twenty-one million, three hundred eleven thousand, three hundred forty-four".