218545640 has 32 divisors (see below), whose sum is σ = 497659680. Its totient is φ = 86363712.

The previous prime is 218545627. The next prime is 218545667. The reversal of 218545640 is 46545812.

It is a self number, because there is not a number n which added to its sum of digits gives 218545640.

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, 29594 + ... + 36233.

It is an arithmetic number, because the mean of its divisors is an integer number (15551865).

Almost surely, 2^218545640 is an apocalyptic number.

218545640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218545640 is an abundant number, since it is smaller than the sum of its proper divisors (279114040).

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

218545640 is a wasteful number, since it uses less digits than its factorization.

218545640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65921 (or 65917 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 35.

The square root of 218545640 is about 14783.2892145152. The cubic root of 218545640 is about 602.3478745651.

The spelling of 218545640 in words is "two hundred eighteen million, five hundred forty-five thousand, six hundred forty".