21120311213 has 4 divisors (see below), whose sum is σ = 22231906560. Its totient is φ = 20008715868.

The previous prime is 21120311203. The next prime is 21120311221. The reversal of 21120311213 is 31211302112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21120311213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21120311191 and 21120311200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120311203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 555797645 + ... + 555797682.

It is an arithmetic number, because the mean of its divisors is an integer number (5557976640).

Almost surely, 2^21120311213 is an apocalyptic number.

It is an amenable number.

21120311213 is a deficient number, since it is larger than the sum of its proper divisors (1111595347).

21120311213 is a wasteful number, since it uses less digits than its factorization.

21120311213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111595346.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21120311213 its reverse (31211302112), we get a palindrome (52331613325).

The spelling of 21120311213 in words is "twenty-one billion, one hundred twenty million, three hundred eleven thousand, two hundred thirteen".