8404421 has 4 divisors (see below), whose sum is σ = 8430144. Its totient is φ = 8378700.

The previous prime is 8404411. The next prime is 8404427. The reversal of 8404421 is 1244048.

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 a de Polignac number, because none of the positive numbers 2^k-8404421 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8404427) 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, 12365 + ... + 13026.

It is an arithmetic number, because the mean of its divisors is an integer number (2107536).

Almost surely, 2^8404421 is an apocalyptic number.

It is an amenable number.

8404421 is a deficient number, since it is larger than the sum of its proper divisors (25723).

8404421 is a wasteful number, since it uses less digits than its factorization.

8404421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25722.

The product of its (nonzero) digits is 1024, while the sum is 23.

The square root of 8404421 is about 2899.0379438703. The cubic root of 8404421 is about 203.3149277138.

Adding to 8404421 its reverse (1244048), we get a palindrome (9648469).

The spelling of 8404421 in words is "eight million, four hundred four thousand, four hundred twenty-one".