218581397 has 8 divisors (see below), whose sum is σ = 228545280. Its totient is φ = 208655920.

The previous prime is 218581379. The next prime is 218581417. The reversal of 218581397 is 793185812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 218581397 - 2¹² = 218577301 is a prime.

It is a super-2 number, since 2×218581397² = 95555654228943218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218581697) by changing a digit.

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, 2372 + ... + 21042.

It is an arithmetic number, because the mean of its divisors is an integer number (28568160).

Almost surely, 2^218581397 is an apocalyptic number.

It is an amenable number.

218581397 is a deficient number, since it is larger than the sum of its proper divisors (9963883).

218581397 is a wasteful number, since it uses less digits than its factorization.

218581397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19203.

The product of its digits is 120960, while the sum is 44.

The square root of 218581397 is about 14784.4985373194. The cubic root of 218581397 is about 602.3807235060.

The spelling of 218581397 in words is "two hundred eighteen million, five hundred eighty-one thousand, three hundred ninety-seven".