21420003 has 32 divisors (see below), whose sum is σ = 32700672. Its totient is φ = 12355200.

The previous prime is 21420001. The next prime is 21420013. The reversal of 21420003 is 30002412.

It is not a de Polignac number, because 21420003 - 2¹ = 21420001 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21420001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64548 + ... + 64878.

It is an arithmetic number, because the mean of its divisors is an integer number (1021896).

Almost surely, 2^21420003 is an apocalyptic number.

21420003 is a deficient number, since it is larger than the sum of its proper divisors (11280669).

21420003 is a wasteful number, since it uses less digits than its factorization.

21420003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435.

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 21420003 is about 4628.1749102643. The cubic root of 21420003 is about 277.7195859554.

Adding to 21420003 its reverse (30002412), we get a palindrome (51422415).

It can be divided in two parts, 21 and 420003, that added together give a palindrome (420024).

The spelling of 21420003 in words is "twenty-one million, four hundred twenty thousand, three".