27978177408 has 128 divisors (see below), whose sum is σ = 77676019200. Its totient is φ = 8905881600.

The previous prime is 27978177391. The next prime is 27978177413. The reversal of 27978177408 is 80477187972.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×27978177408² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 6188973 + ... + 6193491.

It is an arithmetic number, because the mean of its divisors is an integer number (606843900).

Almost surely, 2^27978177408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 27978177408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38838009600).

27978177408 is an abundant number, since it is smaller than the sum of its proper divisors (49697841792).

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

27978177408 is a wasteful number, since it uses less digits than its factorization.

27978177408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5260 (or 5248 counting only the distinct ones).

The product of its (nonzero) digits is 11063808, while the sum is 60.

The spelling of 27978177408 in words is "twenty-seven billion, nine hundred seventy-eight million, one hundred seventy-seven thousand, four hundred eight".