21311004043243 has 4 divisors (see below), whose sum is σ = 21311063686080. Its totient is φ = 21310944400408.

The previous prime is 21311004043211. The next prime is 21311004043291. The reversal of 21311004043243 is 34234040011312.

It is a happy number.

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 21311004043243 - 2⁵ = 21311004043211 is a prime.

It is a super-2 number, since 2×21311004043243² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21311004073243) 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, 29282203 + ... + 30001156.

It is an arithmetic number, because the mean of its divisors is an integer number (5327765921520).

Almost surely, 2^{21311004043243} is an apocalyptic number.

21311004043243 is a deficient number, since it is larger than the sum of its proper divisors (59642837).

21311004043243 is an equidigital number, since it uses as much as digits as its factorization.

21311004043243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59642836.

The product of its (nonzero) digits is 6912, while the sum is 28.

Adding to 21311004043243 its reverse (34234040011312), we get a palindrome (55545044054555).

The spelling of 21311004043243 in words is "twenty-one trillion, three hundred eleven billion, four million, forty-three thousand, two hundred forty-three".