21544021361 has 8 divisors (see below), whose sum is σ = 22468260864. Its totient is φ = 20634111360.

The previous prime is 21544021337. The next prime is 21544021427. The reversal of 21544021361 is 16312044512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21544021361 - 2³⁰ = 20470279537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21544321361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3579305 + ... + 3585318.

It is an arithmetic number, because the mean of its divisors is an integer number (2808532608).

Almost surely, 2^21544021361 is an apocalyptic number.

It is an amenable number.

21544021361 is a deficient number, since it is larger than the sum of its proper divisors (924239503).

21544021361 is an equidigital number, since it uses as much as digits as its factorization.

21544021361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7164751.

The product of its (nonzero) digits is 5760, while the sum is 29.

Adding to 21544021361 its reverse (16312044512), we get a palindrome (37856065873).

The spelling of 21544021361 in words is "twenty-one billion, five hundred forty-four million, twenty-one thousand, three hundred sixty-one".