21212131211 has 8 divisors (see below), whose sum is σ = 21731846400. Its totient is φ = 20693616552.

The previous prime is 21212131153. The next prime is 21212131231. The reversal of 21212131211 is 11213121212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21212131211 - 2³⁰ = 20138389387 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21212131211.

It is not an unprimeable number, because it can be changed into a prime (21212131231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 264311 + ... + 335088.

It is an arithmetic number, because the mean of its divisors is an integer number (2716480800).

Almost surely, 2^21212131211 is an apocalyptic number.

21212131211 is a deficient number, since it is larger than the sum of its proper divisors (519715189).

21212131211 is an equidigital number, since it uses as much as digits as its factorization.

21212131211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600265.

The product of its digits is 48, while the sum is 17.

Adding to 21212131211 its reverse (11213121212), we get a palindrome (32425252423).

Subtracting from 21212131211 its reverse (11213121212), we obtain a palindrome (9999009999).

The spelling of 21212131211 in words is "twenty-one billion, two hundred twelve million, one hundred thirty-one thousand, two hundred eleven".