27878399 has 4 divisors (see below), whose sum is σ = 27888960. Its totient is φ = 27867840.

The previous prime is 27878359. The next prime is 27878423. The reversal of 27878399 is 99387872.

It is a Cunningham number, because it is equal to 5280²-1.

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.

It is a cyclic number.

It is not a de Polignac number, because 27878399 - 2⁸ = 27878143 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 27878399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27878329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2639 + ... + 7919.

It is an arithmetic number, because the mean of its divisors is an integer number (6972240).

Almost surely, 2^27878399 is an apocalyptic number.

27878399 is a deficient number, since it is larger than the sum of its proper divisors (10561).

27878399 is an equidigital number, since it uses as much as digits as its factorization.

27878399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10560.

The product of its digits is 1524096, while the sum is 53.

The square root of 27878399 is about 5279.9999053030. Note that the first 4 decimals coincide. The cubic root of 27878399 is about 303.2186732709.

The spelling of 27878399 in words is "twenty-seven million, eight hundred seventy-eight thousand, three hundred ninety-nine".