21222340 has 12 divisors (see below), whose sum is σ = 44566956. Its totient is φ = 8488928.

The previous prime is 21222293. The next prime is 21222343. The reversal of 21222340 is 4322212.

It can be written as a sum of positive squares in 2 ways, for example, as 3125824 + 18096516 = 1768^2 + 4254^2 .

It is not an unprimeable number, because it can be changed into a prime (21222343) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530539 + ... + 530578.

It is an arithmetic number, because the mean of its divisors is an integer number (3713913).

Almost surely, 2^21222340 is an apocalyptic number.

21222340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222340 is an abundant number, since it is smaller than the sum of its proper divisors (23344616).

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

21222340 is a wasteful number, since it uses less digits than its factorization.

21222340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061126 (or 1061124 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21222340 is about 4606.7711034954. The cubic root of 21222340 is about 276.8626826589.

Adding to 21222340 its reverse (4322212), we get a palindrome (25544552).

The spelling of 21222340 in words is "twenty-one million, two hundred twenty-two thousand, three hundred forty".