30128421 has 4 divisors (see below), whose sum is σ = 40171232. Its totient is φ = 20085612.

The previous prime is 30128411. The next prime is 30128429. The reversal of 30128421 is 12482103.

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 not a de Polignac number, because 30128421 - 2¹⁷ = 29997349 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30128429) 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, 5021401 + ... + 5021406.

It is an arithmetic number, because the mean of its divisors is an integer number (10042808).

Almost surely, 2^30128421 is an apocalyptic number.

It is an amenable number.

30128421 is a deficient number, since it is larger than the sum of its proper divisors (10042811).

30128421 is a wasteful number, since it uses less digits than its factorization.

30128421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10042810.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 30128421 is about 5488.9362357382. The cubic root of 30128421 is about 311.1659904558.

The spelling of 30128421 in words is "thirty million, one hundred twenty-eight thousand, four hundred twenty-one".