21878222 has 8 divisors (see below), whose sum is σ = 32838696. Its totient is φ = 10931992.

The previous prime is 21878149. The next prime is 21878243. The reversal of 21878222 is 22287812.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2048 + ... + 6924.

It is an arithmetic number, because the mean of its divisors is an integer number (4104837).

Almost surely, 2^21878222 is an apocalyptic number.

21878222 is a deficient number, since it is larger than the sum of its proper divisors (10960474).

21878222 is a wasteful number, since it uses less digits than its factorization.

21878222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7122.

The product of its digits is 7168, while the sum is 32.

The square root of 21878222 is about 4677.4161670734. The cubic root of 21878222 is about 279.6859659539.

The spelling of 21878222 in words is "twenty-one million, eight hundred seventy-eight thousand, two hundred twenty-two".