21122121211 has 8 divisors (see below), whose sum is σ = 21166993440. Its totient is φ = 21077275008.

The previous prime is 21122121199. The next prime is 21122121221. The reversal of 21122121211 is 11212122112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21122121211 is a prime.

It is a super-2 number, since 2×21122121211² (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 (21122121221) 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, 2946850 + ... + 2954008.

It is an arithmetic number, because the mean of its divisors is an integer number (2645874180).

Almost surely, 2^21122121211 is an apocalyptic number.

21122121211 is a deficient number, since it is larger than the sum of its proper divisors (44872229).

21122121211 is an equidigital number, since it uses as much as digits as its factorization.

21122121211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13013.

The product of its digits is 32, while the sum is 16.

Adding to 21122121211 its reverse (11212122112), we get a palindrome (32334243323).

Subtracting from 21122121211 its reverse (11212122112), we obtain a palindrome (9909999099).

The spelling of 21122121211 in words is "twenty-one billion, one hundred twenty-two million, one hundred twenty-one thousand, two hundred eleven".