218979440 has 40 divisors (see below), whose sum is σ = 514394160. Its totient is φ = 86685696.

The previous prime is 218979433. The next prime is 218979451. The reversal of 218979440 is 44979812.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 218979391 and 218979400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6350 + ... + 21869.

It is an arithmetic number, because the mean of its divisors is an integer number (12859854).

Almost surely, 2^218979440 is an apocalyptic number.

218979440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218979440 is an abundant number, since it is smaller than the sum of its proper divisors (295414720).

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

218979440 is a wasteful number, since it uses less digits than its factorization.

218979440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28329 (or 28323 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 218979440 is about 14797.9539126191. The cubic root of 218979440 is about 602.7461526412.

The spelling of 218979440 in words is "two hundred eighteen million, nine hundred seventy-nine thousand, four hundred forty".