21123235011 has 4 divisors (see below), whose sum is σ = 28164313352. Its totient is φ = 14082156672.

The previous prime is 21123234907. The next prime is 21123235019. The reversal of 21123235011 is 11053232112.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21123235011 - 2⁹ = 21123234499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21123235019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3520539166 + ... + 3520539171.

It is an arithmetic number, because the mean of its divisors is an integer number (7041078338).

Almost surely, 2^21123235011 is an apocalyptic number.

21123235011 is a deficient number, since it is larger than the sum of its proper divisors (7041078341).

21123235011 is an equidigital number, since it uses as much as digits as its factorization.

21123235011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7041078340.

The product of its (nonzero) digits is 360, while the sum is 21.

Adding to 21123235011 its reverse (11053232112), we get a palindrome (32176467123).

The spelling of 21123235011 in words is "twenty-one billion, one hundred twenty-three million, two hundred thirty-five thousand, eleven".