4128421 has 4 divisors (see below), whose sum is σ = 4503744. Its totient is φ = 3753100.

The previous prime is 4128409. The next prime is 4128427. The reversal of 4128421 is 1248214.

It is the 830-th star number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 4128421 - 2¹¹ = 4126373 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 4128392 and 4128401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4128427) 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, 187645 + ... + 187666.

It is an arithmetic number, because the mean of its divisors is an integer number (1125936).

Almost surely, 2^4128421 is an apocalyptic number.

It is an amenable number.

4128421 is a deficient number, since it is larger than the sum of its proper divisors (375323).

4128421 is a wasteful number, since it uses less digits than its factorization.

4128421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375322.

The product of its digits is 512, while the sum is 22.

The square root of 4128421 is about 2031.8516185982. The cubic root of 4128421 is about 160.4210395015.

The spelling of 4128421 in words is "four million, one hundred twenty-eight thousand, four hundred twenty-one".