218258440 has 32 divisors (see below), whose sum is σ = 492972480. Its totient is φ = 86967232.

The previous prime is 218258423. The next prime is 218258471. The reversal of 218258440 is 44852812.

It is a junction number, because it is equal to n+sod(n) for n = 218258396 and 218258405.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147 + ... + 20893.

It is an arithmetic number, because the mean of its divisors is an integer number (15405390).

Almost surely, 2^218258440 is an apocalyptic number.

218258440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218258440 is an abundant number, since it is smaller than the sum of its proper divisors (274714040).

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

218258440 is a wasteful number, since it uses less digits than its factorization.

218258440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21021 (or 21017 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 34.

The square root of 218258440 is about 14773.5723506537. The cubic root of 218258440 is about 602.0839020228.

The spelling of 218258440 in words is "two hundred eighteen million, two hundred fifty-eight thousand, four hundred forty".