22128021 has 6 divisors (see below), whose sum is σ = 31962710. Its totient is φ = 14752008.

The previous prime is 22128019. The next prime is 22128061. The reversal of 22128021 is 12082122.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21622500 + 505521 = 4650^2 + 711^2 .

It is not a de Polignac number, because 22128021 - 2¹ = 22128019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 22127985 and 22128003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22128011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1229326 + ... + 1229343.

Almost surely, 2^22128021 is an apocalyptic number.

It is an amenable number.

22128021 is a deficient number, since it is larger than the sum of its proper divisors (9834689).

22128021 is a wasteful number, since it uses less digits than its factorization.

22128021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2458675 (or 2458672 counting only the distinct ones).

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

The square root of 22128021 is about 4704.0430482724. The cubic root of 22128021 is about 280.7463971635.

The spelling of 22128021 in words is "twenty-two million, one hundred twenty-eight thousand, twenty-one".