27991397378 has 16 divisors (see below), whose sum is σ = 48006699840. Its totient is φ = 11990951376.

The previous prime is 27991397377. The next prime is 27991397381. The reversal of 27991397378 is 87379319972.

It is not an unprimeable number, because it can be changed into a prime (27991397377) 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 7 ways as a sum of consecutive naturals, for example, 414293 + ... + 477096.

It is an arithmetic number, because the mean of its divisors is an integer number (3000418740).

Almost surely, 2^27991397378 is an apocalyptic number.

27991397378 is a deficient number, since it is larger than the sum of its proper divisors (20015302462).

27991397378 is a wasteful number, since it uses less digits than its factorization.

27991397378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893641.

The product of its digits is 36006768, while the sum is 65.

The spelling of 27991397378 in words is "twenty-seven billion, nine hundred ninety-one million, three hundred ninety-seven thousand, three hundred seventy-eight".