21003321023 has 4 divisors (see below), whose sum is σ = 21006855168. Its totient is φ = 20999786880.

The previous prime is 21003321013. The next prime is 21003321049. The reversal of 21003321023 is 32012330012.

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

It is a cyclic number.

It is not a de Polignac number, because 21003321023 - 2¹⁰ = 21003319999 is a prime.

It is a super-2 number, since 2×21003321023² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21003320992 and 21003321010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003321013) 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, 1758143 + ... + 1770048.

It is an arithmetic number, because the mean of its divisors is an integer number (5251713792).

Almost surely, 2^21003321023 is an apocalyptic number.

21003321023 is a deficient number, since it is larger than the sum of its proper divisors (3534145).

21003321023 is an equidigital number, since it uses as much as digits as its factorization.

21003321023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3534144.

The product of its (nonzero) digits is 216, while the sum is 17.

Adding to 21003321023 its reverse (32012330012), we get a palindrome (53015651035).

The spelling of 21003321023 in words is "twenty-one billion, three million, three hundred twenty-one thousand, twenty-three".