22221000 has 128 divisors (see below), whose sum is σ = 77126400. Its totient is φ = 5918400.

The previous prime is 22220987. The next prime is 22221007. The reversal of 22221000 is 12222.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (22221007) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26589 + ... + 27411.

It is an arithmetic number, because the mean of its divisors is an integer number (602550).

Almost surely, 2^22221000 is an apocalyptic number.

22221000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38563200).

22221000 is an abundant number, since it is smaller than the sum of its proper divisors (54905400).

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

22221000 is a wasteful number, since it uses less digits than its factorization.

22221000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 853 (or 833 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 22221000 is about 4713.9155698846. The cubic root of 22221000 is about 281.1390673620.

Adding to 22221000 its reverse (12222), we get a palindrome (22233222).

The spelling of 22221000 in words is "twenty-two million, two hundred twenty-one thousand".