22281720 has 32 divisors (see below), whose sum is σ = 66845520. Its totient is φ = 5941760.

The previous prime is 22281719. The next prime is 22281751. The reversal of 22281720 is 2718222.

It is a happy number.

It is a super-3 number, since 3×22281720³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92721 + ... + 92960.

Almost surely, 2^22281720 is an apocalyptic number.

22281720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

22281720 is an abundant number, since it is smaller than the sum of its proper divisors (44563800).

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

22281720 is a wasteful number, since it uses less digits than its factorization.

22281720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185695 (or 185691 counting only the distinct ones).

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

The square root of 22281720 is about 4720.3516818135. The cubic root of 22281720 is about 281.3949100157.

Adding to 22281720 its reverse (2718222), we get a palindrome (24999942).

The spelling of 22281720 in words is "twenty-two million, two hundred eighty-one thousand, seven hundred twenty".