21423222 has 48 divisors (see below), whose sum is σ = 50210160. Its totient is φ = 6578496.

The previous prime is 21423221. The next prime is 21423223. The reversal of 21423222 is 22232412.

21423222 is a `hidden beast` number, since 21 + 423 + 222 = 666.

It is an interprime number because it is at equal distance from previous prime (21423221) and next prime (21423223).

It is a super-2 number, since 2×21423222² = 917908881722568, which contains 22 as substring.

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 = 21423195 and 21423204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423221) 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, 11808 + ... + 13500.

It is an arithmetic number, because the mean of its divisors is an integer number (1046045).

Almost surely, 2^21423222 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21423222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25105080).

21423222 is an abundant number, since it is smaller than the sum of its proper divisors (28786938).

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

21423222 is a wasteful number, since it uses less digits than its factorization.

21423222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1757 (or 1754 counting only the distinct ones).

The product of its digits is 384, while the sum is 18.

The square root of 21423222 is about 4628.5226584732. The cubic root of 21423222 is about 277.7334971668.

Adding to 21423222 its reverse (22232412), we get a palindrome (43655634).

It can be divided in two parts, 214 and 23222, that added together give a triangular number (23436 = T₂₁₆).

The spelling of 21423222 in words is "twenty-one million, four hundred twenty-three thousand, two hundred twenty-two".