2178381816 has 64 divisors (see below), whose sum is σ = 6516535200. Its totient is φ = 670270464.

The previous prime is 2178381769. The next prime is 2178381847. The reversal of 2178381816 is 6181838712.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 385081 + ... + 390696.

Almost surely, 2^2178381816 is an apocalyptic number.

2178381816 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

2178381816 is an abundant number, since it is smaller than the sum of its proper divisors (4338153384).

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

2178381816 is a wasteful number, since it uses less digits than its factorization.

2178381816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775805 (or 775795 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 2178381816 is about 46673.1380560596. The cubic root of 2178381816 is about 1296.3173519818.

The spelling of 2178381816 in words is "two billion, one hundred seventy-eight million, three hundred eighty-one thousand, eight hundred sixteen".