21440155504 has 20 divisors (see below), whose sum is σ = 41552905176. Its totient is φ = 10716825152.

The previous prime is 21440155501. The next prime is 21440155511. The reversal of 21440155504 is 40555104412.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440155501) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 148459 + ... + 254794.

Almost surely, 2^21440155504 is an apocalyptic number.

It is an amenable number.

21440155504 is a deficient number, since it is larger than the sum of its proper divisors (20112749672).

21440155504 is a wasteful number, since it uses less digits than its factorization.

21440155504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406584 (or 406578 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 31.

Adding to 21440155504 its reverse (40555104412), we get a palindrome (61995259916).

The spelling of 21440155504 in words is "twenty-one billion, four hundred forty million, one hundred fifty-five thousand, five hundred four".