27881640 has 96 divisors (see below), whose sum is σ = 92874600. Its totient is φ = 7249920.

The previous prime is 27881627. The next prime is 27881671. The reversal of 27881640 is 4618872.

27881640 is a `hidden beast` number, since 2 + 7 + 8 + 8 + 1 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 14791716 + 13089924 = 3846^2 + 3618^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 27881595 and 27881604.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13816 + ... + 15704.

Almost surely, 2^27881640 is an apocalyptic number.

27881640 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 27881640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46437300).

27881640 is an abundant number, since it is smaller than the sum of its proper divisors (64992960).

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

27881640 is a wasteful number, since it uses less digits than its factorization.

27881640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1947 (or 1940 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 27881640 is about 5280.3068092678. The cubic root of 27881640 is about 303.2304230327.

It can be divided in two parts, 278 and 81640, that added together give a palindrome (81918).

The spelling of 27881640 in words is "twenty-seven million, eight hundred eighty-one thousand, six hundred forty".