21044121321 has 16 divisors (see below), whose sum is σ = 28483214400. Its totient is φ = 13817303808.

The previous prime is 21044121281. The next prime is 21044121323. The reversal of 21044121321 is 12312144012.

It is not a de Polignac number, because 21044121321 - 2²¹ = 21042024169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21044121323) 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, 1845325 + ... + 1856693.

It is an arithmetic number, because the mean of its divisors is an integer number (1780200900).

Almost surely, 2^21044121321 is an apocalyptic number.

It is an amenable number.

21044121321 is a deficient number, since it is larger than the sum of its proper divisors (7439093079).

21044121321 is a wasteful number, since it uses less digits than its factorization.

21044121321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20648.

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21044121321 its reverse (12312144012), we get a palindrome (33356265333).

The spelling of 21044121321 in words is "twenty-one billion, forty-four million, one hundred twenty-one thousand, three hundred twenty-one".