7878881 has 4 divisors (see below), whose sum is σ = 7885332. Its totient is φ = 7872432.

The previous prime is 7878877. The next prime is 7878887. The reversal of 7878881 is 1888787.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1888787 = 557 ⋅3391.

It can be written as a sum of positive squares in 2 ways, for example, as 2588881 + 5290000 = 1609^2 + 2300^2 .

It is a cyclic number.

It is not a de Polignac number, because 7878881 - 2² = 7878877 is a prime.

It is a super-2 number, since 2×7878881² = 124153531624322, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian 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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 770 + ... + 4043.

It is an arithmetic number, because the mean of its divisors is an integer number (1971333).

Almost surely, 2^7878881 is an apocalyptic number.

It is an amenable number.

7878881 is a deficient number, since it is larger than the sum of its proper divisors (6451).

7878881 is a wasteful number, since it uses less digits than its factorization.

7878881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6450.

The product of its digits is 200704, while the sum is 47.

The square root of 7878881 is about 2806.9344488249. The cubic root of 7878881 is about 198.9855380347.

The spelling of 7878881 in words is "seven million, eight hundred seventy-eight thousand, eight hundred eighty-one".