21222785 has 8 divisors (see below), whose sum is σ = 25565760. Its totient is φ = 16912624.

The previous prime is 21222757. The next prime is 21222787. The reversal of 21222785 is 58722212.

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 21222785 - 2⁸ = 21222529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21222787) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 6755 + ... + 9384.

It is an arithmetic number, because the mean of its divisors is an integer number (3195720).

Almost surely, 2^21222785 is an apocalyptic number.

It is an amenable number.

21222785 is a deficient number, since it is larger than the sum of its proper divisors (4342975).

21222785 is a wasteful number, since it uses less digits than its factorization.

21222785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16407.

The product of its digits is 4480, while the sum is 29.

The square root of 21222785 is about 4606.8194017131. The cubic root of 21222785 is about 276.8646177744.

Adding to 21222785 its reverse (58722212), we get a palindrome (79944997).

The spelling of 21222785 in words is "twenty-one million, two hundred twenty-two thousand, seven hundred eighty-five".