21220244 has 12 divisors (see below), whose sum is σ = 38333568. Its totient is φ = 10267800.

The previous prime is 21220231. The next prime is 21220261. The reversal of 21220244 is 44202212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85442 + ... + 85689.

It is an arithmetic number, because the mean of its divisors is an integer number (3194464).

Almost surely, 2^21220244 is an apocalyptic number.

It is an amenable number.

21220244 is a deficient number, since it is larger than the sum of its proper divisors (17113324).

21220244 is a wasteful number, since it uses less digits than its factorization.

21220244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171166 (or 171164 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21220244 is about 4606.5436066535. The cubic root of 21220244 is about 276.8535676840.

Adding to 21220244 its reverse (44202212), we get a palindrome (65422456).

The spelling of 21220244 in words is "twenty-one million, two hundred twenty thousand, two hundred forty-four".