21644171303252 has 6 divisors (see below), whose sum is σ = 37877299780698. Its totient is φ = 10822085651624.

The previous prime is 21644171303219. The next prime is 21644171303299. The reversal of 21644171303252 is 25230317144612.

It can be written as a sum of positive squares in only one way, i.e., 18300993097156 + 3343178206096 = 4277966^2 + 1828436^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2705521412903 + ... + 2705521412910.

It is an arithmetic number, because the mean of its divisors is an integer number (6312883296783).

Almost surely, 2^{21644171303252} is an apocalyptic number.

It is an amenable number.

21644171303252 is a deficient number, since it is larger than the sum of its proper divisors (16233128477446).

21644171303252 is a wasteful number, since it uses less digits than its factorization.

21644171303252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5411042825817 (or 5411042825815 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 41.

Adding to 21644171303252 its reverse (25230317144612), we get a palindrome (46874488447864).

The spelling of 21644171303252 in words is "twenty-one trillion, six hundred forty-four billion, one hundred seventy-one million, three hundred three thousand, two hundred fifty-two".