21042105355 has 8 divisors (see below), whose sum is σ = 25495677792. Its totient is φ = 16670250048.

The previous prime is 21042105353. The next prime is 21042105397. The reversal of 21042105355 is 55350124012.

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 21042105355 - 2¹ = 21042105353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21042105353) 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, 20428714 + ... + 20429743.

It is an arithmetic number, because the mean of its divisors is an integer number (3186959724).

Almost surely, 2^21042105355 is an apocalyptic number.

21042105355 is a deficient number, since it is larger than the sum of its proper divisors (4453572437).

21042105355 is a wasteful number, since it uses less digits than its factorization.

21042105355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40858565.

The product of its (nonzero) digits is 6000, while the sum is 28.

Adding to 21042105355 its reverse (55350124012), we get a palindrome (76392229367).

The spelling of 21042105355 in words is "twenty-one billion, forty-two million, one hundred five thousand, three hundred fifty-five".