7878385 has 4 divisors (see below), whose sum is σ = 9454068. Its totient is φ = 6302704.

The previous prime is 7878383. The next prime is 7878391. The reversal of 7878385 is 5838787.

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 861184 + 7017201 = 928^2 + 2649^2 .

It is a cyclic number.

It is not a de Polignac number, because 7878385 - 2¹ = 7878383 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7878383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 787834 + ... + 787843.

It is an arithmetic number, because the mean of its divisors is an integer number (2363517).

Almost surely, 2^7878385 is an apocalyptic number.

It is an amenable number.

7878385 is a deficient number, since it is larger than the sum of its proper divisors (1575683).

7878385 is a wasteful number, since it uses less digits than its factorization.

7878385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1575682.

The product of its digits is 376320, while the sum is 46.

The square root of 7878385 is about 2806.8460948189. The cubic root of 7878385 is about 198.9813623615.

The spelling of 7878385 in words is "seven million, eight hundred seventy-eight thousand, three hundred eighty-five".