21212344 has 16 divisors (see below), whose sum is σ = 39822120. Its totient is φ = 10593120.

The previous prime is 21212297. The next prime is 21212353. The reversal of 21212344 is 44321212.

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, 11314 + ... + 13054.

Almost surely, 2^21212344 is an apocalyptic number.

It is an amenable number.

21212344 is a deficient number, since it is larger than the sum of its proper divisors (18609776).

21212344 is a wasteful number, since it uses less digits than its factorization.

21212344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3270 (or 3266 counting only the distinct ones).

The product of its digits is 384, while the sum is 19.

The square root of 21212344 is about 4605.6860509592. The cubic root of 21212344 is about 276.8192071829.

Adding to 21212344 its reverse (44321212), we get a palindrome (65533556).

It can be divided in two parts, 2121 and 2344, that added together give a triangular number (4465 = T₉₄).

The spelling of 21212344 in words is "twenty-one million, two hundred twelve thousand, three hundred forty-four".