21210344 has 8 divisors (see below), whose sum is σ = 39769410. Its totient is φ = 10605168.

The previous prime is 21210337. The next prime is 21210367. The reversal of 21210344 is 44301212.

It can be written as a sum of positive squares in only one way, i.e., 17056900 + 4153444 = 4130^2 + 2038^2 .

It is a tau number, because it is divible by the number of its divisors (8).

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 as a sum of consecutive naturals, namely, 1325639 + ... + 1325654.

Almost surely, 2^21210344 is an apocalyptic number.

It is an amenable number.

21210344 is a deficient number, since it is larger than the sum of its proper divisors (18559066).

21210344 is a wasteful number, since it uses less digits than its factorization.

21210344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2651299 (or 2651295 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21210344 is about 4605.4689229220. The cubic root of 21210344 is about 276.8105069686.

Adding to 21210344 its reverse (44301212), we get a palindrome (65511556).

The spelling of 21210344 in words is "twenty-one million, two hundred ten thousand, three hundred forty-four".