21904903 has 4 divisors (see below), whose sum is σ = 22072248. Its totient is φ = 21737560.

The previous prime is 21904877. The next prime is 21904943. The reversal of 21904903 is 30940912.

It is a happy number.

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 21904903 - 2⁹ = 21904391 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 (21904943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83476 + ... + 83737.

It is an arithmetic number, because the mean of its divisors is an integer number (5518062).

Almost surely, 2^21904903 is an apocalyptic number.

21904903 is a deficient number, since it is larger than the sum of its proper divisors (167345).

21904903 is a wasteful number, since it uses less digits than its factorization.

21904903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167344.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 21904903 is about 4680.2674068903. The cubic root of 21904903 is about 279.7996142786.

The spelling of 21904903 in words is "twenty-one million, nine hundred four thousand, nine hundred three".