2181978240 has 512 divisors, whose sum is σ = 8143027200. Its totient is φ = 492355584.

The previous prime is 2181978223. The next prime is 2181978257. The reversal of 2181978240 is 428791812.

It is an interprime number because it is at equal distance from previous prime (2181978223) and next prime (2181978257).

It is a super-2 number, since 2×2181978240² = 9522058079666995200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2181978192 and 2181978201.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 20392267 + ... + 20392373.

It is an arithmetic number, because the mean of its divisors is an integer number (15904350).

Almost surely, 2^2181978240 is an apocalyptic number.

2181978240 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 2181978240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4071513600).

2181978240 is an abundant number, since it is smaller than the sum of its proper divisors (5961048960).

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

2181978240 is a wasteful number, since it uses less digits than its factorization.

2181978240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204 (or 192 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 42.

The square root of 2181978240 is about 46711.6499387465. The cubic root of 2181978240 is about 1297.0303496605.

The spelling of 2181978240 in words is "two billion, one hundred eighty-one million, nine hundred seventy-eight thousand, two hundred forty".