21120420011 has 2 divisors, whose sum is σ = 21120420012. Its totient is φ = 21120420010.

The previous prime is 21120419993. The next prime is 21120420017. The reversal of 21120420011 is 11002402112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21120420011 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21120420017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560210005 + 10560210006.

It is an arithmetic number, because the mean of its divisors is an integer number (10560210006).

Almost surely, 2^21120420011 is an apocalyptic number.

21120420011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120420011 is an equidigital number, since it uses as much as digits as its factorization.

21120420011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21120420011 its reverse (11002402112), we get a palindrome (32122822123).

The spelling of 21120420011 in words is "twenty-one billion, one hundred twenty million, four hundred twenty thousand, eleven".