21121211011 has 2 divisors, whose sum is σ = 21121211012. Its totient is φ = 21121211010.

The previous prime is 21121210987. The next prime is 21121211047. The reversal of 21121211011 is 11011212112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21121211011 - 2⁷ = 21121210883 is a prime.

It is a super-2 number, since 2×21121211011² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121210982 and 21121211000.

It is not a weakly prime, because it can be changed into another prime (21121211081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560605505 + 10560605506.

It is an arithmetic number, because the mean of its divisors is an integer number (10560605506).

Almost surely, 2^21121211011 is an apocalyptic number.

21121211011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121211011 is an equidigital number, since it uses as much as digits as its factorization.

21121211011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21121211011 its reverse (11011212112), we get a palindrome (32132423123).

The spelling of 21121211011 in words is "twenty-one billion, one hundred twenty-one million, two hundred eleven thousand, eleven".