21205300343 has 4 divisors (see below), whose sum is σ = 21205649640. Its totient is φ = 21204951048.

The previous prime is 21205300331. The next prime is 21205300373. The reversal of 21205300343 is 34300350212.

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

It is a cyclic number.

It is not a de Polignac number, because 21205300343 - 2¹⁰ = 21205299319 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 (21205300313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57305 + ... + 213762.

It is an arithmetic number, because the mean of its divisors is an integer number (5301412410).

Almost surely, 2^21205300343 is an apocalyptic number.

21205300343 is a deficient number, since it is larger than the sum of its proper divisors (349297).

21205300343 is an equidigital number, since it uses as much as digits as its factorization.

21205300343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349296.

The product of its (nonzero) digits is 2160, while the sum is 23.

Adding to 21205300343 its reverse (34300350212), we get a palindrome (55505650555).

The spelling of 21205300343 in words is "twenty-one billion, two hundred five million, three hundred thousand, three hundred forty-three".