21521011444 has 12 divisors (see below), whose sum is σ = 37887290784. Its totient is φ = 10696071224.

The previous prime is 21521011439. The next prime is 21521011469. The reversal of 21521011444 is 44411012512.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16107874 + ... + 16109209.

It is an arithmetic number, because the mean of its divisors is an integer number (3157274232).

Almost surely, 2^21521011444 is an apocalyptic number.

It is an amenable number.

21521011444 is a deficient number, since it is larger than the sum of its proper divisors (16366279340).

21521011444 is a wasteful number, since it uses less digits than its factorization.

21521011444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32217254 (or 32217252 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 25.

Adding to 21521011444 its reverse (44411012512), we get a palindrome (65932023956).

The spelling of 21521011444 in words is "twenty-one billion, five hundred twenty-one million, eleven thousand, four hundred forty-four".