21130003 has 4 divisors (see below), whose sum is σ = 21811648. Its totient is φ = 20448360.

The previous prime is 21130001. The next prime is 21130027. The reversal of 21130003 is 30003112.

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 21130003 - 2¹ = 21130001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21130001) 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 3 ways as a sum of consecutive naturals, for example, 340776 + ... + 340837.

It is an arithmetic number, because the mean of its divisors is an integer number (5452912).

Almost surely, 2^21130003 is an apocalyptic number.

21130003 is a deficient number, since it is larger than the sum of its proper divisors (681645).

21130003 is an equidigital number, since it uses as much as digits as its factorization.

21130003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 681644.

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21130003 is about 4596.7383001428. The cubic root of 21130003 is about 276.4605618098.

Adding to 21130003 its reverse (30003112), we get a palindrome (51133115).

The spelling of 21130003 in words is "twenty-one million, one hundred thirty thousand, three".