21144212 has 6 divisors (see below), whose sum is σ = 37002378. Its totient is φ = 10572104.

The previous prime is 21144203. The next prime is 21144223. The reversal of 21144212 is 21244112.

It can be written as a sum of positive squares in only one way, i.e., 20394256 + 749956 = 4516^2 + 866^2 .

It is a super-2 number, since 2×21144212² = 894155402201888, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2643023 + ... + 2643030.

It is an arithmetic number, because the mean of its divisors is an integer number (6167063).

Almost surely, 2^21144212 is an apocalyptic number.

It is an amenable number.

21144212 is a deficient number, since it is larger than the sum of its proper divisors (15858166).

21144212 is a wasteful number, since it uses less digits than its factorization.

21144212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5286057 (or 5286055 counting only the distinct ones).

The product of its digits is 128, while the sum is 17.

The square root of 21144212 is about 4598.2835928203. The cubic root of 21144212 is about 276.5225171242.

Adding to 21144212 its reverse (21244112), we get a palindrome (42388324).

The spelling of 21144212 in words is "twenty-one million, one hundred forty-four thousand, two hundred twelve".