27991318320 has 960 divisors, whose sum is σ = 120335155200. Its totient is φ = 5684152320.

The previous prime is 27991318283. The next prime is 27991318337. The reversal of 27991318320 is 2381319972.

27991318320 is a `hidden beast` number, since 2 + 7 + 9 + 9 + 1 + 318 + 320 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 156375991 + ... + 156376169.

It is an arithmetic number, because the mean of its divisors is an integer number (125349120).

Almost surely, 2^27991318320 is an apocalyptic number.

27991318320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 27991318320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (60167577600).

27991318320 is an abundant number, since it is smaller than the sum of its proper divisors (92343836880).

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

27991318320 is a wasteful number, since it uses less digits than its factorization.

27991318320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318 (or 309 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The spelling of 27991318320 in words is "twenty-seven billion, nine hundred ninety-one million, three hundred eighteen thousand, three hundred twenty".