8378921 has 4 divisors (see below), whose sum is σ = 8407812. Its totient is φ = 8350032.

The previous prime is 8378893. The next prime is 8378987. The reversal of 8378921 is 1298738.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8185321 + 193600 = 2861^2 + 440^2 .

It is a cyclic number.

It is not a de Polignac number, because 8378921 - 2⁶ = 8378857 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (8378521) 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, 14006 + ... + 14591.

It is an arithmetic number, because the mean of its divisors is an integer number (2101953).

Almost surely, 2^8378921 is an apocalyptic number.

It is an amenable number.

8378921 is a deficient number, since it is larger than the sum of its proper divisors (28891).

8378921 is a wasteful number, since it uses less digits than its factorization.

8378921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28890.

The product of its digits is 24192, while the sum is 38.

The square root of 8378921 is about 2894.6365920440. The cubic root of 8378921 is about 203.1090922769.

The spelling of 8378921 in words is "eight million, three hundred seventy-eight thousand, nine hundred twenty-one".