665556331 has 8 divisors (see below), whose sum is σ = 741510144. Its totient is φ = 592177320.

The previous prime is 665556271. The next prime is 665556361. The reversal of 665556331 is 133655566.

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

It is a cyclic number.

It is not a de Polignac number, because 665556331 - 2¹³ = 665548139 is a prime.

It is a super-2 number, since 2×665556331² = 885930459468363122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665556361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 643155 + ... + 644188.

It is an arithmetic number, because the mean of its divisors is an integer number (92688768).

Almost surely, 2^665556331 is an apocalyptic number.

665556331 is a deficient number, since it is larger than the sum of its proper divisors (75953813).

665556331 is a wasteful number, since it uses less digits than its factorization.

665556331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1287401.

The product of its digits is 243000, while the sum is 40.

The square root of 665556331 is about 25798.3784567945. The cubic root of 665556331 is about 873.0952114657.

The spelling of 665556331 in words is "six hundred sixty-five million, five hundred fifty-six thousand, three hundred thirty-one".