21212113331 has 4 divisors (see below), whose sum is σ = 22134379152. Its totient is φ = 20289847512.

The previous prime is 21212113327. The next prime is 21212113333. The reversal of 21212113331 is 13331121212.

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 21212113331 - 2² = 21212113327 is a prime.

It is a super-2 number, since 2×21212113331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212113333) 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, 461132876 + ... + 461132921.

It is an arithmetic number, because the mean of its divisors is an integer number (5533594788).

Almost surely, 2^21212113331 is an apocalyptic number.

21212113331 is a deficient number, since it is larger than the sum of its proper divisors (922265821).

21212113331 is an equidigital number, since it uses as much as digits as its factorization.

21212113331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922265820.

The product of its digits is 216, while the sum is 20.

Adding to 21212113331 its reverse (13331121212), we get a palindrome (34543234543).

The spelling of 21212113331 in words is "twenty-one billion, two hundred twelve million, one hundred thirteen thousand, three hundred thirty-one".