665887008361 has 3 divisors (see below), whose sum is σ = 665887824381. Its totient is φ = 665886192342.

The previous prime is 665887008359. The next prime is 665887008463. The reversal of 665887008361 is 163800788566.

The square root of 665887008361 is 816019.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 665887008361 - 2¹ = 665887008359 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665887008296 and 665887008305.

It is not an unprimeable number, because it can be changed into a prime (665887008161) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 408010 + ... + 1224028.

It is an arithmetic number, because the mean of its divisors is an integer number (221962608127).

Almost surely, 2^665887008361 is an apocalyptic number.

665887008361 is the 816019-th square number.

665887008361 is the 408010-th centered octagonal number.

It is an amenable number.

665887008361 is a deficient number, since it is larger than the sum of its proper divisors (816020).

665887008361 is an frugal number, since it uses more digits than its factorization.

665887008361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632038 (or 816019 counting only the distinct ones).

The product of its (nonzero) digits is 11612160, while the sum is 58.

The spelling of 665887008361 in words is "six hundred sixty-five billion, eight hundred eighty-seven million, eight thousand, three hundred sixty-one".