21742200 has 144 divisors (see below), whose sum is σ = 74861280. Its totient is φ = 5652480.

The previous prime is 21742187. The next prime is 21742207. The reversal of 21742200 is 224712.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21742207) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 84472 + ... + 84728.

It is an arithmetic number, because the mean of its divisors is an integer number (519870).

Almost surely, 2^21742200 is an apocalyptic number.

21742200 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 21742200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37430640).

21742200 is an abundant number, since it is smaller than the sum of its proper divisors (53119080).

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

21742200 is a wasteful number, since it uses less digits than its factorization.

21742200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326 (or 314 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21742200 is about 4662.8532037798. The cubic root of 21742200 is about 279.1051363118.

Adding to 21742200 its reverse (224712), we get a palindrome (21966912).

The spelling of 21742200 in words is "twenty-one million, seven hundred forty-two thousand, two hundred".