218993393 has 4 divisors (see below), whose sum is σ = 226057728. Its totient is φ = 211929060.

The previous prime is 218993389. The next prime is 218993399. The reversal of 218993393 is 393399812.

218993393 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 218993393 - 2² = 218993389 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218993399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3532121 + ... + 3532182.

It is an arithmetic number, because the mean of its divisors is an integer number (56514432).

Almost surely, 2^218993393 is an apocalyptic number.

It is an amenable number.

218993393 is a deficient number, since it is larger than the sum of its proper divisors (7064335).

218993393 is an equidigital number, since it uses as much as digits as its factorization.

218993393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7064334.

The product of its digits is 314928, while the sum is 47.

The square root of 218993393 is about 14798.4253554221. The cubic root of 218993393 is about 602.7589543582.

The spelling of 218993393 in words is "two hundred eighteen million, nine hundred ninety-three thousand, three hundred ninety-three".