21228473 has 8 divisors (see below), whose sum is σ = 24594048. Its totient is φ = 17946144.

The previous prime is 21228469. The next prime is 21228509. The reversal of 21228473 is 37482212.

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

It is a cyclic number.

It is not a de Polignac number, because 21228473 - 2² = 21228469 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21228373) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20261 + ... + 21282.

It is an arithmetic number, because the mean of its divisors is an integer number (3074256).

Almost surely, 2^21228473 is an apocalyptic number.

It is an amenable number.

21228473 is a deficient number, since it is larger than the sum of its proper divisors (3365575).

21228473 is an equidigital number, since it uses as much as digits as its factorization.

21228473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41623.

The product of its digits is 5376, while the sum is 29.

The square root of 21228473 is about 4607.4367060221. The cubic root of 21228473 is about 276.8893500810.

The spelling of 21228473 in words is "twenty-one million, two hundred twenty-eight thousand, four hundred seventy-three".