21857422 has 8 divisors (see below), whose sum is σ = 32817816. Its totient is φ = 10918152.

The previous prime is 21857411. The next prime is 21857431. The reversal of 21857422 is 22475812.

It is a happy number.

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, 2373 + ... + 7024.

It is an arithmetic number, because the mean of its divisors is an integer number (4102227).

Almost surely, 2^21857422 is an apocalyptic number.

21857422 is a deficient number, since it is larger than the sum of its proper divisors (10960394).

21857422 is a wasteful number, since it uses less digits than its factorization.

21857422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10562.

The product of its digits is 8960, while the sum is 31.

The square root of 21857422 is about 4675.1921885629. The cubic root of 21857422 is about 279.5973037727.

The spelling of 21857422 in words is "twenty-one million, eight hundred fifty-seven thousand, four hundred twenty-two".