21103331243 has 4 divisors (see below), whose sum is σ = 22020867408. Its totient is φ = 20185795080.

The previous prime is 21103331239. The next prime is 21103331281. The reversal of 21103331243 is 34213330112.

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 21103331243 - 2² = 21103331239 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 917536141 = 21103331243 / (2 + 1 + 1 + 0 + 3 + 3 + 3 + 1 + 2 + 4 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21103331213) 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, 458768048 + ... + 458768093.

It is an arithmetic number, because the mean of its divisors is an integer number (5505216852).

Almost surely, 2^21103331243 is an apocalyptic number.

21103331243 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21103331243 is a deficient number, since it is larger than the sum of its proper divisors (917536165).

21103331243 is an equidigital number, since it uses as much as digits as its factorization.

21103331243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917536164.

The product of its (nonzero) digits is 1296, while the sum is 23.

Adding to 21103331243 its reverse (34213330112), we get a palindrome (55316661355).

The spelling of 21103331243 in words is "twenty-one billion, one hundred three million, three hundred thirty-one thousand, two hundred forty-three".