21202128 has 80 divisors (see below), whose sum is σ = 64460160. Its totient is φ = 6649344.

The previous prime is 21202127. The next prime is 21202133. The reversal of 21202128 is 82120212.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21202128.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5901 + ... + 8787.

It is an arithmetic number, because the mean of its divisors is an integer number (805752).

Almost surely, 2^21202128 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 21202128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32230080).

21202128 is an abundant number, since it is smaller than the sum of its proper divisors (43258032).

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

21202128 is a wasteful number, since it uses less digits than its factorization.

21202128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2921 (or 2909 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 21202128 is about 4604.5768535230. The cubic root of 21202128 is about 276.7747607490.

The spelling of 21202128 in words is "twenty-one million, two hundred two thousand, one hundred twenty-eight".