21504434044 has 12 divisors (see below), whose sum is σ = 37634719024. Its totient is φ = 10751657184.

The previous prime is 21504434041. The next prime is 21504434123. The reversal of 21504434044 is 44043440512.

It is a junction number, because it is equal to n+sod(n) for n = 21504433997 and 21504434015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21504434041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46617 + ... + 212560.

Almost surely, 2^21504434044 is an apocalyptic number.

It is an amenable number.

21504434044 is a deficient number, since it is larger than the sum of its proper divisors (16130284980).

21504434044 is a wasteful number, since it uses less digits than its factorization.

21504434044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279924 (or 279922 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 31.

Adding to 21504434044 its reverse (44043440512), we get a palindrome (65547874556).

The spelling of 21504434044 in words is "twenty-one billion, five hundred four million, four hundred thirty-four thousand, forty-four".