21112111213 has 4 divisors (see below), whose sum is σ = 21510452988. Its totient is φ = 20713769440.

The previous prime is 21112111211. The next prime is 21112111243. The reversal of 21112111213 is 31211121112.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15845270884 + 5266840329 = 125878^2 + 72573^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112111213 - 2¹ = 21112111211 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 (21112111211) 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, 199170808 + ... + 199170913.

It is an arithmetic number, because the mean of its divisors is an integer number (5377613247).

Almost surely, 2^21112111213 is an apocalyptic number.

It is an amenable number.

21112111213 is a deficient number, since it is larger than the sum of its proper divisors (398341775).

21112111213 is an equidigital number, since it uses as much as digits as its factorization.

21112111213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398341774.

The product of its digits is 24, while the sum is 16.

Adding to 21112111213 its reverse (31211121112), we get a palindrome (52323232325).

The spelling of 21112111213 in words is "twenty-one billion, one hundred twelve million, one hundred eleven thousand, two hundred thirteen".