21002144421 has 16 divisors (see below), whose sum is σ = 28488665088. Its totient is φ = 13759796400.

The previous prime is 21002144333. The next prime is 21002144459. The reversal of 21002144421 is 12444120012.

It is not a de Polignac number, because 21002144421 - 2⁹ = 21002143909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002144321) 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, 92281 + ... + 224766.

It is an arithmetic number, because the mean of its divisors is an integer number (1780541568).

Almost surely, 2^21002144421 is an apocalyptic number.

It is an amenable number.

21002144421 is a deficient number, since it is larger than the sum of its proper divisors (7486520667).

21002144421 is a wasteful number, since it uses less digits than its factorization.

21002144421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317432.

The product of its (nonzero) digits is 512, while the sum is 21.

Adding to 21002144421 its reverse (12444120012), we get a palindrome (33446264433).

The spelling of 21002144421 in words is "twenty-one billion, two million, one hundred forty-four thousand, four hundred twenty-one".