21004344543 has 32 divisors (see below), whose sum is σ = 36496244736. Its totient is φ = 10427493888.

The previous prime is 21004344539. The next prime is 21004344589. The reversal of 21004344543 is 34544340012.

It is not a de Polignac number, because 21004344543 - 2² = 21004344539 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21004344543.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004344503) 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 31 ways as a sum of consecutive naturals, for example, 2258271 + ... + 2267552.

It is an arithmetic number, because the mean of its divisors is an integer number (1140507648).

Almost surely, 2^21004344543 is an apocalyptic number.

21004344543 is a deficient number, since it is larger than the sum of its proper divisors (15491900193).

21004344543 is a wasteful number, since it uses less digits than its factorization.

21004344543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4525863.

The product of its (nonzero) digits is 23040, while the sum is 30.

Adding to 21004344543 its reverse (34544340012), we get a palindrome (55548684555).

The spelling of 21004344543 in words is "twenty-one billion, four million, three hundred forty-four thousand, five hundred forty-three".