21311023543 has 8 divisors (see below), whose sum is σ = 22240522368. Its totient is φ = 20381769144.

The previous prime is 21311023537. The next prime is 21311023571. The reversal of 21311023543 is 34532011312.

It is a happy number.

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 21311023543 - 2¹³ = 21311015351 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 (21311023043) 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, 129796 + ... + 243862.

It is an arithmetic number, because the mean of its divisors is an integer number (2780065296).

Almost surely, 2^21311023543 is an apocalyptic number.

21311023543 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21311023543 is a deficient number, since it is larger than the sum of its proper divisors (929498825).

21311023543 is a wasteful number, since it uses less digits than its factorization.

21311023543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122213.

The product of its (nonzero) digits is 2160, while the sum is 25.

Adding to 21311023543 its reverse (34532011312), we get a palindrome (55843034855).

The spelling of 21311023543 in words is "twenty-one billion, three hundred eleven million, twenty-three thousand, five hundred forty-three".