2003000021 has 4 divisors (see below), whose sum is σ = 2185090944. Its totient is φ = 1820909100.

The previous prime is 2002999981. The next prime is 2003000029. The reversal of 2003000021 is 1200003002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2003000021 - 2¹⁰ = 2002998997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2002999972 and 2003000008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2003000029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 91045445 + ... + 91045466.

It is an arithmetic number, because the mean of its divisors is an integer number (546272736).

Almost surely, 2^2003000021 is an apocalyptic number.

It is an amenable number.

2003000021 is a deficient number, since it is larger than the sum of its proper divisors (182090923).

2003000021 is a wasteful number, since it uses less digits than its factorization.

2003000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182090922.

The product of its (nonzero) digits is 12, while the sum is 8.

The square root of 2003000021 is about 44754.8882358117. Note that the first 3 decimals coincide. The cubic root of 2003000021 is about 1260.5507001071.

Adding to 2003000021 its reverse (1200003002), we get a palindrome (3203003023).

The spelling of 2003000021 in words is "two billion, three million, twenty-one", and thus it is an aban number and an uban number.