218138140 has 48 divisors (see below), whose sum is σ = 511378560. Its totient is φ = 77474880.

The previous prime is 218138111. The next prime is 218138143. The reversal of 218138140 is 41831812.

It is a junction number, because it is equal to n+sod(n) for n = 218138099 and 218138108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218138143) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2070 + ... + 20989.

It is an arithmetic number, because the mean of its divisors is an integer number (10653720).

Almost surely, 2^218138140 is an apocalyptic number.

218138140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218138140 is an abundant number, since it is smaller than the sum of its proper divisors (293240420).

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

218138140 is a wasteful number, since it uses less digits than its factorization.

218138140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23122 (or 23120 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 218138140 is about 14769.5003300721. The cubic root of 218138140 is about 601.9732625366.

Adding to 218138140 its reverse (41831812), we get a palindrome (259969952).

The spelling of 218138140 in words is "two hundred eighteen million, one hundred thirty-eight thousand, one hundred forty".