21042444405 has 16 divisors (see below), whose sum is σ = 34219845504. Its totient is φ = 11038658880.

The previous prime is 21042444383. The next prime is 21042444407. The reversal of 21042444405 is 50444424012.

It is not a de Polignac number, because 21042444405 - 2³¹ = 18894960757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042444407) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11497689 + ... + 11499518.

It is an arithmetic number, because the mean of its divisors is an integer number (2138740344).

Almost surely, 2^21042444405 is an apocalyptic number.

It is an amenable number.

21042444405 is a deficient number, since it is larger than the sum of its proper divisors (13177401099).

21042444405 is a wasteful number, since it uses less digits than its factorization.

21042444405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22997276.

The product of its (nonzero) digits is 20480, while the sum is 30.

Adding to 21042444405 its reverse (50444424012), we get a palindrome (71486868417).

The spelling of 21042444405 in words is "twenty-one billion, forty-two million, four hundred forty-four thousand, four hundred five".