8427921 has 4 divisors (see below), whose sum is σ = 11237232. Its totient is φ = 5618612.

The previous prime is 8427911. The next prime is 8427929. The reversal of 8427921 is 1297248.

It is a happy 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 8427921 - 2¹⁰ = 8426897 is a prime.

8427921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (8427929) 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, 1404651 + ... + 1404656.

It is an arithmetic number, because the mean of its divisors is an integer number (2809308).

Almost surely, 2^8427921 is an apocalyptic number.

It is an amenable number.

8427921 is a deficient number, since it is larger than the sum of its proper divisors (2809311).

8427921 is a wasteful number, since it uses less digits than its factorization.

8427921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2809310.

The product of its digits is 8064, while the sum is 33.

The square root of 8427921 is about 2903.0881832972. The cubic root of 8427921 is about 203.5042508675.

The spelling of 8427921 in words is "eight million, four hundred twenty-seven thousand, nine hundred twenty-one".