21046003 has 4 divisors (see below), whose sum is σ = 22959288. Its totient is φ = 19132720.

The previous prime is 21046001. The next prime is 21046009. The reversal of 21046003 is 30064012.

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 21046003 - 2¹ = 21046001 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21046001) 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, 956626 + ... + 956647.

It is an arithmetic number, because the mean of its divisors is an integer number (5739822).

Almost surely, 2^21046003 is an apocalyptic number.

21046003 is a deficient number, since it is larger than the sum of its proper divisors (1913285).

21046003 is a wasteful number, since it uses less digits than its factorization.

21046003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1913284.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21046003 is about 4587.5922879000. The cubic root of 21046003 is about 276.0937291057.

Subtracting 21046003 from its reverse (30064012), we obtain a square (9018009 = 3003²).

The spelling of 21046003 in words is "twenty-one million, forty-six thousand, three".