21201128 has 16 divisors (see below), whose sum is σ = 42810180. Its totient is φ = 9785088.

The previous prime is 21201127. The next prime is 21201133. The reversal of 21201128 is 82110212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16630084 + 4571044 = 4078^2 + 2138^2 .

It is not an unprimeable number, because it can be changed into a prime (21201121) 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, 101825 + ... + 102032.

Almost surely, 2^21201128 is an apocalyptic number.

It is an amenable number.

21201128 is an abundant number, since it is smaller than the sum of its proper divisors (21609052).

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

21201128 is a wasteful number, since it uses less digits than its factorization.

21201128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203876 (or 203872 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 21201128 is about 4604.4682646317. The cubic root of 21201128 is about 276.7704093130.

The spelling of 21201128 in words is "twenty-one million, two hundred one thousand, one hundred twenty-eight".