21001320344 has 16 divisors (see below), whose sum is σ = 39435996120. Its totient is φ = 10485054720.

The previous prime is 21001320343. The next prime is 21001320367. The reversal of 21001320344 is 44302310012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001320343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1944962 + ... + 1955729.

Almost surely, 2^21001320344 is an apocalyptic number.

It is an amenable number.

21001320344 is a deficient number, since it is larger than the sum of its proper divisors (18434675776).

21001320344 is a wasteful number, since it uses less digits than its factorization.

21001320344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3901370 (or 3901366 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21001320344 its reverse (44302310012), we get a palindrome (65303630356).

The spelling of 21001320344 in words is "twenty-one billion, one million, three hundred twenty thousand, three hundred forty-four".