21331302123 has 12 divisors (see below), whose sum is σ = 29231212920. Its totient is φ = 13836517632.

The previous prime is 21331302119. The next prime is 21331302169. The reversal of 21331302123 is 32120313312.

It is not a de Polignac number, because 21331302123 - 2² = 21331302119 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21331302123.

It is not an unprimeable number, because it can be changed into a prime (21331302173) 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 11 ways as a sum of consecutive naturals, for example, 2592838 + ... + 2601051.

It is an arithmetic number, because the mean of its divisors is an integer number (2435934410).

Almost surely, 2^21331302123 is an apocalyptic number.

21331302123 is a deficient number, since it is larger than the sum of its proper divisors (7899910797).

21331302123 is an equidigital number, since it uses as much as digits as its factorization.

21331302123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5193966 (or 5193929 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 21.

Adding to 21331302123 its reverse (32120313312), we get a palindrome (53451615435).

The spelling of 21331302123 in words is "twenty-one billion, three hundred thirty-one million, three hundred two thousand, one hundred twenty-three".