7878889 has 4 divisors (see below), whose sum is σ = 7892356. Its totient is φ = 7865424.

The previous prime is 7878887. The next prime is 7878911. The reversal of 7878889 is 9888787.

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 632025 + 7246864 = 795^2 + 2692^2 .

It is a cyclic number.

It is not a de Polignac number, because 7878889 - 2¹ = 7878887 is a prime.

It is a Duffinian number.

7878889 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7878887) 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, 5814 + ... + 7039.

It is an arithmetic number, because the mean of its divisors is an integer number (1973089).

Almost surely, 2^7878889 is an apocalyptic number.

It is an amenable number.

7878889 is a deficient number, since it is larger than the sum of its proper divisors (13467).

7878889 is a wasteful number, since it uses less digits than its factorization.

7878889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13466.

The product of its digits is 1806336, while the sum is 55.

The square root of 7878889 is about 2806.9358738667. The cubic root of 7878889 is about 198.9856053829.

The spelling of 7878889 in words is "seven million, eight hundred seventy-eight thousand, eight hundred eighty-nine".