664218355 has 4 divisors (see below), whose sum is σ = 797062032. Its totient is φ = 531374680.

The previous prime is 664218323. The next prime is 664218383. The reversal of 664218355 is 553812466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 553812466 = 2 ⋅276906233.

It is not a de Polignac number, because 664218355 - 2⁵ = 664218323 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66421831 + ... + 66421840.

It is an arithmetic number, because the mean of its divisors is an integer number (199265508).

Almost surely, 2^664218355 is an apocalyptic number.

664218355 is a deficient number, since it is larger than the sum of its proper divisors (132843677).

664218355 is a wasteful number, since it uses less digits than its factorization.

664218355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132843676.

The product of its digits is 172800, while the sum is 40.

The square root of 664218355 is about 25772.4340138839. The cubic root of 664218355 is about 872.5097543265.

The spelling of 664218355 in words is "six hundred sixty-four million, two hundred eighteen thousand, three hundred fifty-five".