21223044 has 18 divisors (see below), whose sum is σ = 53647230. Its totient is φ = 7074336.

The previous prime is 21223009. The next prime is 21223051. The reversal of 21223044 is 44032212.

It can be written as a sum of positive squares in only one way, i.e., 20358144 + 864900 = 4512^2 + 930^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 294729 + ... + 294800.

Almost surely, 2^21223044 is an apocalyptic number.

It is an amenable number.

21223044 is an abundant number, since it is smaller than the sum of its proper divisors (32424186).

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

21223044 is a wasteful number, since it uses less digits than its factorization.

21223044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589539 (or 589534 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 21223044 is about 4606.8475121280. The cubic root of 21223044 is about 276.8657440426.

Adding to 21223044 its reverse (44032212), we get a palindrome (65255256).

The spelling of 21223044 in words is "twenty-one million, two hundred twenty-three thousand, forty-four".