21144391543 has 8 divisors (see below), whose sum is σ = 23067827856. Its totient is φ = 19221158400.

The previous prime is 21144391519. The next prime is 21144391553. The reversal of 21144391543 is 34519344112.

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 21144391543 - 2²¹ = 21142294391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144391553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 238473 + ... + 314893.

It is an arithmetic number, because the mean of its divisors is an integer number (2883478482).

Almost surely, 2^21144391543 is an apocalyptic number.

21144391543 is a deficient number, since it is larger than the sum of its proper divisors (1923436313).

21144391543 is a wasteful number, since it uses less digits than its factorization.

21144391543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101585.

The product of its digits is 51840, while the sum is 37.

The spelling of 21144391543 in words is "twenty-one billion, one hundred forty-four million, three hundred ninety-one thousand, five hundred forty-three".