21223438 has 8 divisors (see below), whose sum is σ = 32000688. Its totient is φ = 10556544.

The previous prime is 21223427. The next prime is 21223453. The reversal of 21223438 is 83432212.

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

It is a congruent number.

It is an unprimeable number.

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, 27106 + ... + 27877.

It is an arithmetic number, because the mean of its divisors is an integer number (4000086).

Almost surely, 2^21223438 is an apocalyptic number.

21223438 is a deficient number, since it is larger than the sum of its proper divisors (10777250).

21223438 is a wasteful number, since it uses less digits than its factorization.

21223438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55178.

The product of its digits is 2304, while the sum is 25.

The square root of 21223438 is about 4606.8902743608. The cubic root of 21223438 is about 276.8674573442.

The spelling of 21223438 in words is "twenty-one million, two hundred twenty-three thousand, four hundred thirty-eight".