21045222 has 48 divisors (see below), whose sum is σ = 50134032. Its totient is φ = 6327360.

The previous prime is 21045197. The next prime is 21045229. The reversal of 21045222 is 22254012.

21045222 is a `hidden beast` number, since 210 + 452 + 2 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21045195 and 21045204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21045229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30748 + ... + 31424.

It is an arithmetic number, because the mean of its divisors is an integer number (1044459).

Almost surely, 2^21045222 is an apocalyptic number.

21045222 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21045222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25067016).

21045222 is an abundant number, since it is smaller than the sum of its proper divisors (29088810).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21045222 is a wasteful number, since it uses less digits than its factorization.

21045222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 853 (or 850 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 21045222 is about 4587.5071662069. The cubic root of 21045222 is about 276.0903138592.

Adding to 21045222 its reverse (22254012), we get a palindrome (43299234).

The spelling of 21045222 in words is "twenty-one million, forty-five thousand, two hundred twenty-two".