665618398 has 8 divisors (see below), whose sum is σ = 998702208. Its totient is φ = 332717664.

The previous prime is 665618347. The next prime is 665618399. The reversal of 665618398 is 893816566.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665618399) 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, 36286 + ... + 51457.

It is an arithmetic number, because the mean of its divisors is an integer number (124837776).

Almost surely, 2^665618398 is an apocalyptic number.

665618398 is a deficient number, since it is larger than the sum of its proper divisors (333083810).

665618398 is a wasteful number, since it uses less digits than its factorization.

665618398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91538.

The product of its digits is 1866240, while the sum is 52.

The square root of 665618398 is about 25799.5813531925. The cubic root of 665618398 is about 873.1223510247.

The spelling of 665618398 in words is "six hundred sixty-five million, six hundred eighteen thousand, three hundred ninety-eight".