21850128 has 80 divisors (see below), whose sum is σ = 64460160. Its totient is φ = 7081344.

The previous prime is 21850099. The next prime is 21850177. The reversal of 21850128 is 82105812.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15301 + ... + 16667.

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

Almost surely, 2^21850128 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 21850128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32230080).

21850128 is an abundant number, since it is smaller than the sum of its proper divisors (42610032).

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

21850128 is a wasteful number, since it uses less digits than its factorization.

21850128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1421 (or 1409 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 21850128 is about 4674.4120485896. The cubic root of 21850128 is about 279.5661990122.

The spelling of 21850128 in words is "twenty-one million, eight hundred fifty thousand, one hundred twenty-eight".