21073903 has 4 divisors (see below), whose sum is σ = 21278608. Its totient is φ = 20869200.

The previous prime is 21073891. The next prime is 21073909. The reversal of 21073903 is 30937012.

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 21073903 - 2⁹ = 21073391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21073909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102198 + ... + 102403.

It is an arithmetic number, because the mean of its divisors is an integer number (5319652).

Almost surely, 2^21073903 is an apocalyptic number.

21073903 is a deficient number, since it is larger than the sum of its proper divisors (204705).

21073903 is a wasteful number, since it uses less digits than its factorization.

21073903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204704.

The product of its (nonzero) digits is 1134, while the sum is 25.

The square root of 21073903 is about 4590.6320915534. The cubic root of 21073903 is about 276.2156780520.

The spelling of 21073903 in words is "twenty-one million, seventy-three thousand, nine hundred three".