22781220 has 96 divisors (see below), whose sum is σ = 79543296. Its totient is φ = 4732800.

The previous prime is 22781197. The next prime is 22781221. The reversal of 22781220 is 2218722.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (22781221) 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 31 ways as a sum of consecutive naturals, for example, 2155 + ... + 7085.

It is an arithmetic number, because the mean of its divisors is an integer number (828576).

Almost surely, 2^22781220 is an apocalyptic number.

22781220 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 22781220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39771648).

22781220 is an abundant number, since it is smaller than the sum of its proper divisors (56762076).

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

22781220 is a wasteful number, since it uses less digits than its factorization.

22781220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4961 (or 4959 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 22781220 is about 4772.9676303114. The cubic root of 22781220 is about 283.4821117896.

Adding to 22781220 its reverse (2218722), we get a palindrome (24999942).

The spelling of 22781220 in words is "twenty-two million, seven hundred eighty-one thousand, two hundred twenty".