21904473 has 8 divisors (see below), whose sum is σ = 30743200. Its totient is φ = 13834368.

The previous prime is 21904471. The next prime is 21904489. The reversal of 21904473 is 37440912.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21904473 - 2¹ = 21904471 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21904473.

It is not an unprimeable number, because it can be changed into a prime (21904471) 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 7 ways as a sum of consecutive naturals, for example, 192088 + ... + 192201.

It is an arithmetic number, because the mean of its divisors is an integer number (3842900).

Almost surely, 2^21904473 is an apocalyptic number.

It is an amenable number.

21904473 is a deficient number, since it is larger than the sum of its proper divisors (8838727).

21904473 is a wasteful number, since it uses less digits than its factorization.

21904473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384311.

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 21904473 is about 4680.2214691187. The cubic root of 21904473 is about 279.7977834157.

The spelling of 21904473 in words is "twenty-one million, nine hundred four thousand, four hundred seventy-three".