21030003 has 16 divisors (see below), whose sum is σ = 32988960. Its totient is φ = 13195008.

The previous prime is 21030001. The next prime is 21030043. The reversal of 21030003 is 30003012.

It is a happy number.

It is not a de Polignac number, because 21030003 - 2¹ = 21030001 is a prime.

It is a super-2 number, since 2×21030003² = 884522052360018, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21030001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22450 + ... + 23367.

It is an arithmetic number, because the mean of its divisors is an integer number (2061810).

Almost surely, 2^21030003 is an apocalyptic number.

21030003 is a deficient number, since it is larger than the sum of its proper divisors (11958957).

21030003 is a wasteful number, since it uses less digits than its factorization.

21030003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45843 (or 45837 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 9.

The square root of 21030003 is about 4585.8481222125. The cubic root of 21030003 is about 276.0237455940.

Adding to 21030003 its reverse (30003012), we get a palindrome (51033015).

The spelling of 21030003 in words is "twenty-one million, thirty thousand, three".