21040243444 has 24 divisors (see below), whose sum is σ = 41552834400. Its totient is φ = 9233962080.

The previous prime is 21040243397. The next prime is 21040243451. The reversal of 21040243444 is 44434204012.

It is a super-3 number, since 3×21040243444³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8243334 + ... + 8245885.

It is an arithmetic number, because the mean of its divisors is an integer number (1731368100).

Almost surely, 2^21040243444 is an apocalyptic number.

It is an amenable number.

21040243444 is a deficient number, since it is larger than the sum of its proper divisors (20512590956).

21040243444 is a wasteful number, since it uses less digits than its factorization.

21040243444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16489263 (or 16489261 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 28.

Adding to 21040243444 its reverse (44434204012), we get a palindrome (65474447456).

The spelling of 21040243444 in words is "twenty-one billion, forty million, two hundred forty-three thousand, four hundred forty-four".