2178942840 has 192 divisors, whose sum is σ = 7394587200. Its totient is φ = 555749376.

The previous prime is 2178942833. The next prime is 2178942841. The reversal of 2178942840 is 482498712.

2178942840 is a `hidden beast` number, since 217 + 8 + 9 + 428 + 4 + 0 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2178942841) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1178797 + ... + 1180643.

It is an arithmetic number, because the mean of its divisors is an integer number (38513475).

Almost surely, 2^2178942840 is an apocalyptic number.

2178942840 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 2178942840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3697293600).

2178942840 is an abundant number, since it is smaller than the sum of its proper divisors (5215644360).

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

2178942840 is a wasteful number, since it uses less digits than its factorization.

2178942840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2006 (or 1999 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The square root of 2178942840 is about 46679.1478071312. The cubic root of 2178942840 is about 1296.4286276568.

The spelling of 2178942840 in words is "two billion, one hundred seventy-eight million, nine hundred forty-two thousand, eight hundred forty".