8421399 has 12 divisors (see below), whose sum is σ = 13902096. Its totient is φ = 4812192.

The previous prime is 8421251. The next prime is 8421403. The reversal of 8421399 is 9931248.

It is not a de Polignac number, because 8421399 - 2⁸ = 8421143 is a prime.

It is a super-2 number, since 2×8421399² = 141839922234402, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8421799) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 66774 + ... + 66899.

It is an arithmetic number, because the mean of its divisors is an integer number (1158508).

Almost surely, 2^8421399 is an apocalyptic number.

8421399 is a deficient number, since it is larger than the sum of its proper divisors (5480697).

8421399 is a wasteful number, since it uses less digits than its factorization.

8421399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133686 (or 133683 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 8421399 is about 2901.9646793164. The cubic root of 8421399 is about 203.4517429699.

The spelling of 8421399 in words is "eight million, four hundred twenty-one thousand, three hundred ninety-nine".