8421997 has 4 divisors (see below), whose sum is σ = 8865280. Its totient is φ = 7978716.

The previous prime is 8421991. The next prime is 8422019. The reversal of 8421997 is 7991248.

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 8421997 - 2³ = 8421989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8421991) 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, 221613 + ... + 221650.

It is an arithmetic number, because the mean of its divisors is an integer number (2216320).

Almost surely, 2^8421997 is an apocalyptic number.

It is an amenable number.

8421997 is a deficient number, since it is larger than the sum of its proper divisors (443283).

8421997 is a wasteful number, since it uses less digits than its factorization.

8421997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 443282.

The product of its digits is 36288, while the sum is 40.

The square root of 8421997 is about 2902.0677111329. The cubic root of 8421997 is about 203.4565585301.

The spelling of 8421997 in words is "eight million, four hundred twenty-one thousand, nine hundred ninety-seven".