21111153123 has 4 divisors (see below), whose sum is σ = 28148204168. Its totient is φ = 14074102080.

The previous prime is 21111153103. The next prime is 21111153131. The reversal of 21111153123 is 32135111112.

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

It is not a de Polignac number, because 21111153123 - 2⁹ = 21111152611 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 21111153123.

It is not an unprimeable number, because it can be changed into a prime (21111153103) 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 in 3 ways as a sum of consecutive naturals, for example, 3518525518 + ... + 3518525523.

It is an arithmetic number, because the mean of its divisors is an integer number (7037051042).

Almost surely, 2^21111153123 is an apocalyptic number.

21111153123 is a deficient number, since it is larger than the sum of its proper divisors (7037051045).

21111153123 is an equidigital number, since it uses as much as digits as its factorization.

21111153123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7037051044.

The product of its digits is 180, while the sum is 21.

Adding to 21111153123 its reverse (32135111112), we get a palindrome (53246264235).

The spelling of 21111153123 in words is "twenty-one billion, one hundred eleven million, one hundred fifty-three thousand, one hundred twenty-three".