21003321003123 has 16 divisors (see below), whose sum is σ = 29418132729600. Its totient is φ = 13303533343584.

The previous prime is 21003321003097. The next prime is 21003321003173. The reversal of 21003321003123 is 32130012330012.

It is not a de Polignac number, because 21003321003123 - 2¹⁸ = 21003320740979 is a prime.

It is a super-2 number, since 2×21003321003123² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21003321003123.

It is not an unprimeable number, because it can be changed into a prime (21003321003173) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1021452661 + ... + 1021473222.

It is an arithmetic number, because the mean of its divisors is an integer number (1838633295600).

Almost surely, 2^{21003321003123} is an apocalyptic number.

21003321003123 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21003321003123 is a deficient number, since it is larger than the sum of its proper divisors (8414811726477).

21003321003123 is a wasteful number, since it uses less digits than its factorization.

21003321003123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2042926058.

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

Adding to 21003321003123 its reverse (32130012330012), we get a palindrome (53133333333135).

The spelling of 21003321003123 in words is "twenty-one trillion, three billion, three hundred twenty-one million, three thousand, one hundred twenty-three".