218187940 has 24 divisors (see below), whose sum is σ = 459116280. Its totient is φ = 87099648.

The previous prime is 218187923. The next prime is 218187943. The reversal of 218187940 is 49781812.

It is a happy number.

218187940 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 12208036 + 205979904 = 3494^2 + 14352^2 .

It is a super-2 number, since 2×218187940² = 95211954322887200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 218187893 and 218187902.

It is not an unprimeable number, because it can be changed into a prime (218187943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 537 + ... + 20896.

It is an arithmetic number, because the mean of its divisors is an integer number (19129845).

Almost surely, 2^218187940 is an apocalyptic number.

218187940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218187940 is an abundant number, since it is smaller than the sum of its proper divisors (240928340).

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

218187940 is a wasteful number, since it uses less digits than its factorization.

218187940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21951 (or 21949 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 40.

The square root of 218187940 is about 14771.1861405914. The cubic root of 218187940 is about 602.0190683540.

The spelling of 218187940 in words is "two hundred eighteen million, one hundred eighty-seven thousand, nine hundred forty".