218478381 has 32 divisors (see below), whose sum is σ = 328648320. Its totient is φ = 127948800.

The previous prime is 218478367. The next prime is 218478391. The reversal of 218478381 is 183874812.

It is not a de Polignac number, because 218478381 - 2⁹ = 218477869 is a prime.

It is a super-2 number, since 2×218478381² = 95465605928762322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218478301) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 152175 + ... + 153603.

It is an arithmetic number, because the mean of its divisors is an integer number (10270260).

Almost surely, 2^218478381 is an apocalyptic number.

It is an amenable number.

218478381 is a deficient number, since it is larger than the sum of its proper divisors (110169939).

218478381 is a wasteful number, since it uses less digits than its factorization.

218478381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1597.

The product of its digits is 86016, while the sum is 42.

The square root of 218478381 is about 14781.0142074216. The cubic root of 218478381 is about 602.2860759213.

The spelling of 218478381 in words is "two hundred eighteen million, four hundred seventy-eight thousand, three hundred eighty-one".