27981912978 has 24 divisors (see below), whose sum is σ = 63818398800. Its totient is φ = 8836393464.

The previous prime is 27981912971. The next prime is 27981912989. The reversal of 27981912978 is 87921918972.

It is not an unprimeable number, because it can be changed into a prime (27981912971) 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 11 ways as a sum of consecutive naturals, for example, 40908888 + ... + 40909571.

It is an arithmetic number, because the mean of its divisors is an integer number (2659099950).

Almost surely, 2^27981912978 is an apocalyptic number.

27981912978 is an abundant number, since it is smaller than the sum of its proper divisors (35836485822).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

27981912978 is a wasteful number, since it uses less digits than its factorization.

27981912978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81818486 (or 81818483 counting only the distinct ones).

The product of its digits is 9144576, while the sum is 63.

The spelling of 27981912978 in words is "twenty-seven billion, nine hundred eighty-one million, nine hundred twelve thousand, nine hundred seventy-eight".