21442220 has 24 divisors (see below), whose sum is σ = 45574704. Its totient is φ = 8472896.

The previous prime is 21442163. The next prime is 21442229. The reversal of 21442220 is 2224412.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21442229) 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 7 ways as a sum of consecutive naturals, for example, 4799 + ... + 8118.

It is an arithmetic number, because the mean of its divisors is an integer number (1898946).

Almost surely, 2^21442220 is an apocalyptic number.

21442220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21442220 is an abundant number, since it is smaller than the sum of its proper divisors (24132484).

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

21442220 is a wasteful number, since it uses less digits than its factorization.

21442220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13009 (or 13007 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21442220 is about 4630.5744783990. The cubic root of 21442220 is about 277.8155704431.

Adding to 21442220 its reverse (2224412), we get a palindrome (23666632).

The spelling of 21442220 in words is "twenty-one million, four hundred forty-two thousand, two hundred twenty".