21323444 has 12 divisors (see below), whose sum is σ = 38226468. Its totient is φ = 10401600.

The previous prime is 21323441. The next prime is 21323473. The reversal of 21323444 is 44432312.

It can be written as a sum of positive squares in 2 ways, for example, as 620944 + 20702500 = 788^2 + 4550^2 .

It is a super-2 number, since 2×21323444² = 909378528042272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64847 + ... + 65174.

It is an arithmetic number, because the mean of its divisors is an integer number (3185539).

Almost surely, 2^21323444 is an apocalyptic number.

It is an amenable number.

21323444 is a deficient number, since it is larger than the sum of its proper divisors (16903024).

21323444 is a wasteful number, since it uses less digits than its factorization.

21323444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130066 (or 130064 counting only the distinct ones).

The product of its digits is 2304, while the sum is 23.

The square root of 21323444 is about 4617.7314776847. The cubic root of 21323444 is about 277.3016476117.

Adding to 21323444 its reverse (44432312), we get a palindrome (65755756).

The spelling of 21323444 in words is "twenty-one million, three hundred twenty-three thousand, four hundred forty-four".