21231554353543 has 4 divisors (see below), whose sum is σ = 21805380146920. Its totient is φ = 20657728560168.

The previous prime is 21231554353417. The next prime is 21231554353571. The reversal of 21231554353543 is 34535345513212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21231554353543 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21231554353493 and 21231554353502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231554353043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 286912896633 + ... + 286912896706.

It is an arithmetic number, because the mean of its divisors is an integer number (5451345036730).

Almost surely, 2^{21231554353543} is an apocalyptic number.

21231554353543 is a deficient number, since it is larger than the sum of its proper divisors (573825793377).

21231554353543 is an equidigital number, since it uses as much as digits as its factorization.

21231554353543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 573825793376.

The product of its digits is 3240000, while the sum is 46.

Adding to 21231554353543 its reverse (34535345513212), we get a palindrome (55766899866755).

The spelling of 21231554353543 in words is "twenty-one trillion, two hundred thirty-one billion, five hundred fifty-four million, three hundred fifty-three thousand, five hundred forty-three".