21121330123 has 4 divisors (see below), whose sum is σ = 22039648848. Its totient is φ = 20203011400.

The previous prime is 21121330121. The next prime is 21121330127. The reversal of 21121330123 is 32103312112.

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

It is not a de Polignac number, because 21121330123 - 2¹ = 21121330121 is a prime.

It is a super-2 number, since 2×21121330123² (a number of 21 digits) contains 22 as substring.

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 21121330123.

It is not an unprimeable number, because it can be changed into a prime (21121330121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 459159328 + ... + 459159373.

It is an arithmetic number, because the mean of its divisors is an integer number (5509912212).

Almost surely, 2^21121330123 is an apocalyptic number.

21121330123 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21121330123 is a deficient number, since it is larger than the sum of its proper divisors (918318725).

21121330123 is an equidigital number, since it uses as much as digits as its factorization.

21121330123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 918318724.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21121330123 its reverse (32103312112), we get a palindrome (53224642235).

The spelling of 21121330123 in words is "twenty-one billion, one hundred twenty-one million, three hundred thirty thousand, one hundred twenty-three".