27791440 has 80 divisors (see below), whose sum is σ = 68276880. Its totient is φ = 10506240.

The previous prime is 27791437. The next prime is 27791441. The reversal of 27791440 is 4419772.

It can be written as a sum of positive squares in 8 ways, for example, as 501264 + 27290176 = 708^2 + 5224^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 27791396 and 27791405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27791441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 121246 + ... + 121474.

It is an arithmetic number, because the mean of its divisors is an integer number (853461).

Almost surely, 2^27791440 is an apocalyptic number.

27791440 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 27791440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34138440).

27791440 is an abundant number, since it is smaller than the sum of its proper divisors (40485440).

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

27791440 is a wasteful number, since it uses less digits than its factorization.

27791440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 314 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 34.

The square root of 27791440 is about 5271.7587198202. The cubic root of 27791440 is about 302.9030758114.

The spelling of 27791440 in words is "twenty-seven million, seven hundred ninety-one thousand, four hundred forty".