21211213243 has 6 divisors (see below), whose sum is σ = 23314804772. Its totient is φ = 19282921020.

The previous prime is 21211213241. The next prime is 21211213267. The reversal of 21211213243 is 34231211212.

It is not a de Polignac number, because 21211213243 - 2¹ = 21211213241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21211213241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 87649521 + ... + 87649762.

Almost surely, 2^21211213243 is an apocalyptic number.

21211213243 is a deficient number, since it is larger than the sum of its proper divisors (2103591529).

21211213243 is a wasteful number, since it uses less digits than its factorization.

21211213243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175299305 (or 175299294 counting only the distinct ones).

The product of its digits is 576, while the sum is 22.

Adding to 21211213243 its reverse (34231211212), we get a palindrome (55442424455).

The spelling of 21211213243 in words is "twenty-one billion, two hundred eleven million, two hundred thirteen thousand, two hundred forty-three".