21742208 has 32 divisors (see below), whose sum is σ = 44064000. Its totient is φ = 10683136.

The previous prime is 21742207. The next prime is 21742211. The reversal of 21742208 is 80224712.

It is a tau number, because it is divible by the number of its divisors (32).

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 3 ways as a sum of consecutive naturals, for example, 6113 + ... + 8991.

It is an arithmetic number, because the mean of its divisors is an integer number (1377000).

Almost surely, 2^21742208 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21742208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22032000).

21742208 is an abundant number, since it is smaller than the sum of its proper divisors (22321792).

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

21742208 is an equidigital number, since it uses as much as digits as its factorization.

21742208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2952 (or 2940 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 21742208 is about 4662.8540616236. The cubic root of 21742208 is about 279.1051705438.

The spelling of 21742208 in words is "twenty-one million, seven hundred forty-two thousand, two hundred eight".