2181784140 has 192 divisors, whose sum is σ = 7159864320. Its totient is φ = 550471680.

The previous prime is 2181784139. The next prime is 2181784147. The reversal of 2181784140 is 414871812.

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 = 2181784095 and 2181784104.

It is not an unprimeable number, because it can be changed into a prime (2181784147) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 1203835 + ... + 1205645.

It is an arithmetic number, because the mean of its divisors is an integer number (37290960).

Almost surely, 2^2181784140 is an apocalyptic number.

2181784140 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 2181784140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3579932160).

2181784140 is an abundant number, since it is smaller than the sum of its proper divisors (4978080180).

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

2181784140 is a wasteful number, since it uses less digits than its factorization.

2181784140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1949 (or 1941 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 2181784140 is about 46709.5722523767. The cubic root of 2181784140 is about 1296.9918889872.

The spelling of 2181784140 in words is "two billion, one hundred eighty-one million, seven hundred eighty-four thousand, one hundred forty".