218923445 has 18 divisors (see below), whose sum is σ = 285030918. Its totient is φ = 161348928.

The previous prime is 218923429. The next prime is 218923451. The reversal of 218923445 is 544329812.

It can be written as a sum of positive squares in 9 ways, for example, as 53260804 + 165662641 = 7298^2 + 12871^2 .

It is not a de Polignac number, because 218923445 - 2⁴ = 218923429 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 218923399 and 218923408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 429851 + ... + 430359.

It is an arithmetic number, because the mean of its divisors is an integer number (15835051).

Almost surely, 2^218923445 is an apocalyptic number.

It is an amenable number.

218923445 is a deficient number, since it is larger than the sum of its proper divisors (66107473).

218923445 is an frugal number, since it uses more digits than its factorization.

218923445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1049 (or 527 counting only the distinct ones).

The product of its digits is 69120, while the sum is 38.

The square root of 218923445 is about 14796.0618071161. The cubic root of 218923445 is about 602.6947724020.

The spelling of 218923445 in words is "two hundred eighteen million, nine hundred twenty-three thousand, four hundred forty-five".