21222442 has 4 divisors (see below), whose sum is σ = 31833666. Its totient is φ = 10611220.

The previous prime is 21222433. The next prime is 21222469. The reversal of 21222442 is 24422212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21077281 + 145161 = 4591^2 + 381^2 .

It is a zygodrome in base 4.

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 as a sum of consecutive naturals, namely, 5305609 + ... + 5305612.

Almost surely, 2^21222442 is an apocalyptic number.

21222442 is a deficient number, since it is larger than the sum of its proper divisors (10611224).

21222442 is a wasteful number, since it uses less digits than its factorization.

21222442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10611223.

The product of its digits is 512, while the sum is 19.

The square root of 21222442 is about 4606.7821741428. The cubic root of 21222442 is about 276.8631262159.

Adding to 21222442 its reverse (24422212), we get a palindrome (45644654).

The spelling of 21222442 in words is "twenty-one million, two hundred twenty-two thousand, four hundred forty-two".